Biological poisons. The term toxin is reserved for any toxicant of biological origin. Toxin fall into several broad categories based on the organism that produce them. Bacteria Fungi: Mycotoxins Algae: Phycotoxins Plant: Phytotoxins Animal: Zootoxins. BACTERIAL TOXIN.
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The term toxin is reserved for any toxicant of biological origin. Toxin fall into several broad categories based on the organism that produce them.
Neurotoxin proteins (Anaerobic condition)
Clostridium botulinum. (A-G)
The most acutely substance, with lethal dose 200-300 pg/kg (100 grams could kill most of human on earth)
Toxin is composed of 2 polypeptide chains that are connected by a disulfide bond:
Light chain 50-kD
Heavy chain 100-kD
Protease enzyme (attack on Fusion protein) at neuromuscular junction, preventing neurotransmitter vesicles from anchoring to the membrane.
Inhibit acetylcholine release
Interferes with nerve impulses.
Produce paralysis of muscles.
Is important for targeting the toxin to specific types of axon terminals.
Attaches the toxin to proteins on the surface of axon terminals so that it can be taken into neurons by endocytosis.
Treatment: Antitoxin antibodies
Casual agent: Clostridium tetani.
Greek (tetanos: Stretched, rigid).
Tetnospasmin or Spasmogenic toxin.
Endotoxin is not secreted in soluble form by bacteria as are exotoxins but rather in chemical components in the cell wall of bacteria that is released when the bacteria lyses (e.g. LPS)
Lowering of blood pressure.
Nausea, Vomiting, Abdominal Cramping.
Disulfiram like effects
No symptoms unless alcohol is consumed with in 2-3 days.
Coma, Convulsion, Excitement, Depression.
Destruction of cells, especially liver and kideny
Aflatoxins(Produced by molds)
Tropical & subtropical (Temperature, humidity high).
Acute cases (Liver damage).
Chronic cases associated with liver cancer.
108 people died from eating contaminated grains (India).
Killed 100,000 turkeys that were eating moldy peanuts.
Aflatoxins B1 is most potent HEPATOCARCINOGEN.
Contamination of rye by Calvicepspurpurea(Ergot fungus)
Convulsive Symptoms(e.g., Painful seizures and spasms, diarrhea, Itching, headaches, nausea and vomiting)
Central Nervous System Symptoms(e.g., hysteria, mania or psychosis).
Gangrenous symptoms (e.g., dry gangrene due to vasoconstriction of distal structures, fingers and toes; weak peripheral pulse; loss of peripheral sensation; edema; ultimately death and loss of affected tissues).
(Pain first at localized at lymph nodes,Nausea,hypertension,transiet tachycardia, bradycardia,profuse sweating, oliguria, cramps)
Inject venom into skin (0.1mm) 0.002mg
Death stalker (L. quinquestriatus)
Local tissue injury
Honey bee (2.8mg/kg)
Velvet ant (71mg/kg)
Paper wasp (2.4mg/kg)
Yellow jacket (3.5mg/kg)
Fire ants (0.66mg/kg)
Treatment: vinegar, ice pack
Blue ringed octopus.
Painlessly kill a human with in 5 min.
Inject neuromuscular venom
maculotoxin and tetrodotoxin.
Conusgeographus (cigarette snail)
Amnesic shellfish poisoning.
Diarrheic shellfish poisoning.
Neurotoxin shellfish poisoning.
Paralytic shellfish poisoning.
Poison dart or “poison arrow”
100 toxins identified in the skin secretions of poison dart frogs (Dendrobates & Phyllobates).
Phyllobates produce neurotoxin, batrachotoxin.
LD50 . 50µg
Some toads produce epinephrine, norepinephrine.
3,500 species of snakes worldwide.
Venomous snakes fall into six families:
Poison is inhaled/ingested, venom is injected.
Hemotoxic heart and cardiovascular system.
Cytotoxic local damage.
Neurotoxic brain and nervous system.
Viperidae is hemotoxic and cytotoxic.
Hydrophiidae and laticaudidaeneurotxic.
Snake venom complex mixture.
The typical venom consist of 25 different enzymes.
The most damaging is proteolytic enzyme (proteases,peptidases,proteinases,hydrolases).
First was described more than 100y ago.
Horses, sheep exposed to graduated doses of venom until become hyper immunized
Animal derived antivenin have potential for hypersensitivity and anaphylaxis.
A cocktail of antivenins can be used against broad range of venoms.