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Micro: Damage by Microbial Toxins
Terms in this set (21)
How does gas gangrene cause cell lysis?
Releases a toxin that effects the integrity of the cell membranes-->lysis of rbcs
How does rocky mountain spotted fever cause cell lysis?
The microorganism multiplies within the host cell, leading to lysis from the inside.
What are some examples of sporulating bacteria?
Clostridium; botulism, gas gangrene and tetanus. Bacillus; anthrax
What is the AB organization of diptheria toxin?
What is the AB organization of anthrax toxin?
What is the AB organization of cholera toxin?
What type of toxin are the botulinum and tetanus toxins?
Neurotoxins ie zinc proteases
What does diptheria toxin do?
Blocks host cell protein synthesis. The A domain, ADP-ribosylates EF-2 catalyzing the hydrolysis of GTP.
What does cholera toxin do?
It DOES NOT kill the target cell. Modulates normal cell function by increasing intracellular cAMP levels. The target for cholera is the epithelium of the small intestine. The A domain ADP-ribosylates a G protein to the active GTP-bound form, where it continuously increases cAMP.
What does the B domain of cholera toxin bind to?
GM1a on the intestinal mucosa.
What effect does the increased intracellular cAMP found in cholera toxin have on the body?
Increases movement of water and ions into the lumen of the gut.
What effect do tetanus and botulism toxin have on the body, respectively?
Tetanus-->muscle contraction ie spastic paralysis. Botulism-->blocks muscle contraction ie flaccid paralysis.
What is the action of the A domain in botulinum toxin?
Inactivates vesicle fusion at the peripheral nerve ending so no stimulatory NT can be released.
What is the action of the A domain in tetanus toxin?
Migrates up the axon to inactivate vesicle fusion at the interneuronal junction to inhibit the release of inhibitory NT.
What is endotoxin?
The LPS of the outer membrane of gram-negative bacteria.
What is special about phagocytes, neutrophils, platelets and B lymphocytes that they are special targets for endotoxin?
Possess toll-like receptors which are endotoxin receptors. Binding results in the production of cytokines
What specific cytokines are thought to be responsible for the development of fever in the presence of endotoxin?
IL-1 and TNF-alpha
What is the equivalent to endotoxin in gram-positive bacteria?
What is Waterhouse-Friderichsen Syndrome?
In some caes of menigococcal infection, DIC leads to adrenal insufficiency and rapid death.
What is an example of a homogenous pore former?
What is an example of a heterogenous pore former?
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