Ask A Scientist© Molecular Biology Archive

name         aleksandra
status       student
age          20s

Question -   why is the bacterial cell wall a
good target for antibacterial action
>Once the cell wall is there it is not a good target,
>but the enzymes that produce bacterial cell walls are
>very specific, and sensitive to specific inhibitors.
>In that way we can produce specific antibiotics that
>are harmless to our own cells. These antibiotics are
>bacteriostatic (they stop bacyteria from growing) in
>stead of bacteriocidic (killing existing bacteria).
>That can be of key importance, since dead bacteria may
>release highly toxic compounds in vaste amounts. In
>other words, killing all pathogenic bacteria present
>in your body during a serious infection (like sepsis)
>can be life-threatening. In that case it is better to
>stop the bacteria from multiplying, and let the body
>cope with the existing bugs.
>
>Trudy Wassenaar
=========================================================
>Bacteria cannot properly divide unless they can make new walls. So
>inhibiting the production of new cell wall (as ampicillin does, for example)
>is one way of preventing bacteria from multiplying. Drugs such as
>ampicillin do not kill bacteria - they only prevent them from dividing. Our
>bodies' defenses then can kill the original bacteria without having to worry
>about their tremendously rapid rate of multiplication.
>----------
Mayo
=========================================================
>Because it's easy to reach. If you target something INSIDE the bacterium,
>you have to somehow get there.
Barrans
=========================================================
>The bacterial cell wall contains chemicals not found in either cell membranes
>or plant or fungal cell walls. This chemical is called peptidoglycan which
>is sugar-protein substance. It is made of two sugars- n-acetyl-muramic acid
>and n-acetyl-glucosamine. These sugars alternate and are linked by a
>tetrapeptide (four amino acids). Gram positive bacteria have cell wall that
>is very thick and is mostly peptidoglycan (PG). Gram negative cell walls are
>not as thick and have other components as well. So, how do antibiotics
>affect only bacteria? They usually affect the cross-linking of the sugars by
>the tetrapeptides and make the walls unstable so that osmotic changes cause
>them to burst. This is how penicillin works. It is more effective against
>gram positive organisms because their cell walls contain more PG. This is
>why a doctor may order a gram stain before precribing antibiotics so he/she
>knows which antibiotic to order.
>
>van hoeck
=========================================================