Amyloid (mycology)
Encyclopedia
In mycology
the term amyloid refers to a crude chemical test using iodine
in either Melzer's reagent
or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch
gives a similar reaction, and that reaction for starch is also called an amyloid reaction. The test can either be on microscopic features, such as spore walls or hyphal walls, or the apical apparatus on an ascus
, or be a macroscopic reaction on tissue where a drop of the reagent is applied. Negative reactions, called inamyloid or nonamyloid reactions are for structures that remain pale brown or clear. A deep reddish to reddish brown reaction is termed either a pseudoamyloid reaction or a dextrinoid reaction.
Mycology
Mycology is the branch of biology concerned with the study of fungi, including their genetic and biochemical properties, their taxonomy and their use to humans as a source for tinder, medicinals , food and entheogens, as well as their dangers, such as poisoning or...
the term amyloid refers to a crude chemical test using iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
in either Melzer's reagent
Melzer's Reagent
Melzer's reagent is a chemical reagent used by mycologists to assist with the identification of fungi.-Composition:...
or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...
gives a similar reaction, and that reaction for starch is also called an amyloid reaction. The test can either be on microscopic features, such as spore walls or hyphal walls, or the apical apparatus on an ascus
Ascus
An ascus is the sexual spore-bearing cell produced in ascomycete fungi. On average, asci normally contain eight ascospores, produced by a meiotic cell division followed, in most species, by a mitotic cell division. However, asci in some genera or species can number one , two, four, or multiples...
, or be a macroscopic reaction on tissue where a drop of the reagent is applied. Negative reactions, called inamyloid or nonamyloid reactions are for structures that remain pale brown or clear. A deep reddish to reddish brown reaction is termed either a pseudoamyloid reaction or a dextrinoid reaction.