Country: United States
Date: March 2005
What is the rule of peptidoglycan (in bacteria cell
wall)in bacteria resistant ?
I'm not sure what you mean by "rule" in resistant bacteria. But
peptidoglycan is a sugar-protein complex found in bacterial cell
walls. It is made of two alternating sugar types that are found in
long sheets. The sheets are linked together by four amino acids
called tetrapeptides. So peptidoglycan is kind of like a chain link
fence surrounding the outside of a bacterium. Many antibiotics work
by "clipping" the tetrapeptide links that hold the wall together.
This makes the wall unstable and the bacterium ruptures under osmotic
pressure, killing the organism. Some bacteria have evolved ways to
inactivate this mechanism. One way is to inactivate the antibiotic so
it can't clip the tetrapeptides anymore. This is an enzyme called
"penicillinase" (actually beta-lactamase) because it breaks down the
penicillin before the penicillin can break down the cell wall. This
makes the bacteria resistant to the penicillin.
The rule is that bacteria which have a cell wall comprised of
peptidoglycan (sugar and amino acid molecules bonded together) are
Gram positive meaning they take up Gram stain
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Update: June 2012