2. Cell wall of fungi is generally constructed
of 3 layers:
1. α-glucan layer – a glucan is a polymer of
glucose
2. ß-glucan layer
3. Outer layer of glycoprotein
In addition, chitin may be a significant
component of certain cell wall structures.
3. Generally composed of the α (1-3)
glucan polymer.
However, α (1-4) glycosides are variably
present.
Α-glucan material appears as a fibrillar
layer adjacent to the plasma membrane
and is thought to serve a largely
structural role, stiffening the basal layer
of the cell wall.
4. α-glucan layer does not occur in
Saccharomyces.
Among ascomycetes, the α-glucan is
found in Schizosaccharomyces, but is
not known from any other yeasts.
5. α-glucans also form a significant,
sometimes even dominant, part of the
cell wall in many basidiomycetes.
6. The bulk material of cell wall is usually in
the form of ß (1-3) glucan.
This forms a very stable hydrogen-bonded tripe,
helix in solution.
The packing of these triple helix structures
appears to be controlled by the size and
frequency of very short (1-6) side chains,
sometimes consisting of only a single glucose
monomer.
7. In addition to ß (1-3) glucan, cell wall contains
ß (1-6) glucan.
This is not simply a ß (1-3) glucan with big side
chains, but a polysaccharide with a true ß (1-6)
backbone.
It is strongly involved in cross linking the various
components of the cell wall.
8. The outermost layer of the cell wall os
composed of diverse proteins bearing
polysaccharide side chains composed
of mannose..
These are attached through their
mannan side chains via (1-3) linkage
with ß (1-6) glucan.
Real life appears to be very much complex,
involving different interactions between
glycoproteins and bulk cell wall materials.
9. In many systems chitin is a major
constituent of the cell wall.
In others, it is involved only in cell division
or reproductive structures and is virtually
absent otherwise.
10.
11. Glucomannan is a water-soluble polysaccharide.
As a dietary fiber, it possesses several potential health
benefits, which include treatment of constipation, decline in
total cholesterol and low-density lipoprotein, increase of
insulin sensitivity, weight loss and also wound healing.
12.
13.
14. Fenugreek galactomannans is used as food emulsifiers.
The detection of galactomannan at concentrations as low
as 1 ng/ml can
be useful for the early initiation of antifungal therapy and
monitoring
treatment in clinically documented lung aspergillosis.
