Module 5: Carbohydrate Staining Flashcards
What are the two carbohydrate functional groups?
Glycogen and mucins
What is glycogen?
Simple polysaccharide, glucose precursor
Where is glycogen found?
Liver, cardiac and skeletal muscle, endocervix, umbilical cord, and hair follicles
What are mucins?
Glycoconjugates, mucopolysaccharides, and mucosubstances
What do mucins do?
Lubrication and favorable diffusion environment
Anti-adhesive nature in bladder
What are the reactive endgroups of carbohydrates?
1,2 glycol groups
Carboxyl (COOH)
Ester sulphate (OSO3H)
What are polysaccharides bound to?
Protein or in protein environment
What are the 4 groups of carbohydrates?
Group 1: Neutral polysaccharides
Group 2: Acid Mucopolysaccharides
Group 3: Glycoproteins
Group 4: Glycolipids
What are the 2 sub groups of group 1 neutral polysaccharides?
Give examples.
Glucose containing - glycogen, starch, cellulose
N-acetyl-glucosamine-containing - chitin-hyatid cysts
Is glycogen bound to protein or in a protein environment? Why is this important?
Protein environment
Some will move from its original site during fixation
How do members of group 1 stain?
PAS positive
Negative for all other carbohydrate stains
What sub groups are part of group 2: acid mucopolysaccharides? Give examples
Carboxylated (COOH) - hyaluronic acid
Sulphated - not containing hexuronic aicd
Carbodylated and sulphated - chondroitin sulphate A, B, and C
Where are carboxylated mucopolysaccharides found?
Connective tissue, synovial fluid, umbilical cord
Where are sulphated mucopolysaccharides found?
Aorta
Where are sulphated and carboxylated mucopolysaccharides found?
Chondroitin sulphate A - hyaline cartilage
Chondroitin sulphate B - skin, aorta, lung, heart valves
Chondroitin C - skin, blood vessels, cornea, umbilical cord
Heparin in mast cells
Heparin sulfate of arterial intima
How will Group 2: Acid mucopolysaccharides stain?
PAS negative
Alcian blue, colloidal iron, and mucicarmine positve
How are group 2 acid mucopolysaccharides differentiated?
Alcian blue 1.0 and 2.5
Hyaluronidase digestion
What subgroups are in group 3: glycoproteins? Give examples
Neutral - stomach mucin, paneth cell granules
Carboxylated - sialoglycoproteins with no sulphate
Sulphated and carboxylated - sialoglycoproteins containing sialic acid and sulphate
Where are sialoglycoproteins found?
Sialomucins - small intestine mucins, submaxillary and sublingual glands
Serum glycoprotein
Blood group substances
How do group 3: glycoproteins stain?
Potential to be PAS positive
Alcian blue positive
How are sialomucins differentiated?
Alcian blue at varying pH
Sialidase digestion
Where are group 3: glycoproteins usually found?
Epithelium
What are the subgroups of group 4: glycolipids? Give examples
Cerebrosides - carbs bound to fat in CNS
Phosphatides - lecithin (cell memberanes), cephalin (brain and spinal cord), sphinomyelin (cell membrane myelin sheath)
How do group 4: glycolipids stain?
PAS positive
