Last minute quick view - Toxins

Assalamualaikum everyone. In the name of Allah the Most Beneficent the Most Merciful.

Toxins. It used to come out in the exam. Just afraid that they'll re-emerge like H1N1 or probably smallpox, I'm planning to 'vaccinate' myself and those who are concerned. BTW they're at the back of our notes (the very old very early notes probably inherited from the times of Adam and Eve). :P

Differences between endotoxins and endotoxins

Property	Endotoxins	Exotoxins
Chemical nature	LPS (lipid A – toxic)	Polypeptide
Relationship to bacteria	Part of outer membrane of G- bacteria	Soluble, secreted extracellularly
Denaturation by boiling	No	Yes
Antigenicity	Yes, weak	Yes, strong
Forms toxoid?	No	Yes
Potency	Less	Very
Specificity	No	Yes
Pyrogenicity	Yes	Hmmm, no.

Exotoxins

3 types:

1. Neurotoxins
2. Cytotoxins
3. Enterotoxins

Name of toxin	Bacteria involved	Activity
Anthrax toxin (EF)	Bacillus anthracis	Edema factor (EF)  is an adenylate cyclase that causes increased levels in intracellular cyclic AMP in phagocytes and formation of ion-permeable pores in membranes (hemolysis).
Adenylate cyclase toxin	Bordetella pertussis	Acts locally to increase levels of cyclic AMP in phagocytes and formation of ion-permeable pores in membranes (hemolysis).
Cholera enterotoxin (choleragen)	Vibrio cholerae	ADP ribocylation of G proteins stimulates adenylate cyclase and increases cAMP in cells of the GI tract, causing secretion of water and electrolytes.
E. coli LT toxin	Escherichia coli	Similar to cholera toxin
E. coli ST toxin	Escherichia coli	Stimulates guanyate cyclase and promotes secretion of water and electrolytes from intestinal epithelium.
Shiga toxin	Shigella dysentriae	Enzymatically cleaves rRNA resulting in inhibition of protein synthesis in susceptible cells.
Perfringens enterotoxin	Clostridium perfringens	Stimulates adenylate cyclase leading to increased cAMP in epithelial cells.
Botulinum toxin	Clostridium botulinum	Zn2+-dependent protease that inhibits neurotransmission in neuromuscular synapse resulting in flaccid paralysis.
Tetanus toxin	Clostridium tetani	Zn2+-dependent protease that inhibits neurotransmission in inhibitory synapses in the spinal cord resulting in spastic paralysis.
Diphtheria toxin	Corynebacterium diphtheriae	ADP ribocylation of elongation factor 2 leading to inhibition of protein synthesis in target cells.
Exotoxin A	Pseudomonas aeruginosa	Inhibits protein synthesis, similar to diphtheria toxin.
Anthrax toxin (LF)	Bacillus anthracis	Lethal factor (LF) is a Zn2+-dependent protease that induces cytokine release and is cytotoxic to cells by an unknown mechanism
Pertussis toxin	Bordetella pertussis	ADP riboxylation of G proteins blocks inhibition of adenylate cyclase in susceptible cells.
Staphylococcus enterotoxins	Staphylococcus aureus	Massive activation of the immune system, including lymphocytes and macrophages, leads to emesis.
Toxic shock syndrome toxin (TSST-1)	Staphylococcus aureus	Acts on the vascular system causing inflammation, fever and shock.
Exfoliation toxin	Staphylococcus aureus	Cleavage of epidermal cells (intradermal separation).
Erythrogenic toxin (scarlet fever toxin)	Streptococcus pyogenes	Causes skin erythematous reactions.