chitin is in the cell wall of fungi.
chitin is in the cell wall of fungi.
what is in the cell wall of fungi?
chitin
section::::fungal cell walls.









































there are several groups of organisms that have been called "fungi". some of these groups (oomycete and myxogastria) have been transferred out of the kingdom fungi, in part because of fundamental biochemical differences in the composition of the cell wall. most true fungi have a cell wall consisting largely of chitin and other polysaccharides. true fungi do not have cellulose in their cell walls.









































section::::fungal cell walls.:true fungi.









































in fungi, the cell wall is the outer-most layer, external to the plasma membrane. the fungal cell wall is a matrix of three main components:
cell wall
penicillin, its derivatives and methicilin, are beta-lactams that all work by disrupting the mechanical structure of the bacterial cell wall by reacting with the cell wall forming penicillin-binding protein family (pbp 1,2, 3 and 4), causing the cytoplasm to leak and the cell to die. however, the meca gene codes for pbp2a, that has a lower affinity for antibiotic drugs, which keeps the structural integrity of the cell wall, preventing cell death. the synthesis of the bacterial cell wall in "s. aureus" is dependent on transglycosylation, to form linear polymer of sugar monomers, and transpeptidation, to form an interlinking peptides to strengthen the newly developed cell wall. pbps have a transpeptidase domain, but transglycosylation was thought to only be carried out by monofunctional enzymes, however pbp2 has domains to carry out both essential processes. when antibiotics are introduced to the medium, they bind to the transpeptidation domain and inhibit the ability of pbps to cross-link muropeptides, therefore preventing the formation of stable cell wall. however, with cooperative action, pbp2a lacks the proper receptor for the antibiotics and continues the transpeptidation, preventing the breakdown of the cell wall. the functionality of pbp2a is dependent on two structural factors on the cell wall of "s. aureus." first, there in order for pbp2a to properly fit onto the cell wall, to continue transpeptidation, requires proper amino acid residues, specifically a pentaglycine residue and an amidated glutamate residue. furthermore, pbp2a has an effective transpeptidase activity, but lacks a transglycosylation domain of pbp2, which builds the backbone of the cell wall with polysaccharide monomers, and so pbp2a must rely on pbp2 to continue this process. the latter of these factors is an enzymatic reaction that can be targeted to improve the ability of beta-lactams to prevent cell wall synthesis in resistant "s." aureus. identification of genetic inhibitors of glycosylases involved in the cell wall synthesis, and modulating the expression of these inhibitors can resensitize these previously resistant bacteria to beta-lactam treatment. for example, epicatechin gallate, a compound found in green tea, has shown signs of lowering the resistance to beta-lactams, to the point where oxacillin becomes effective to inhibit the formation of the cell wall, by inhibiting pbp2 and pbp2a.
meca (gene)