Biological poisons
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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.
BacteriaFungi: MycotoxinsAlgae: PhycotoxinsPlant: PhytotoxinsAnimal: Zootoxins
BACTERIAL TOXIN
Botulinum ToxinNeurotoxin 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)
BotulismToxin is composed of 2 polypeptide chains that
are connected by a disulfide bond: Light chain 50-kD Heavy chain 100-kD
Light chain of the toxinProtease 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.
Heavy chain of toxin
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.
Flaccid paralysisTreatment: Antitoxin antibodies
BOTOX/DYSPORT
Tetanus toxin
Casual agent: Clostridium tetani.Greek (tetanos: Stretched, rigid).Neuromuscular toxin.Tetnospasmin or Spasmogenic toxin.“Lockjaw”
TETNOSPASMIN
Heavy chain 100-KdLight chain 50-kD
Interferewith protein vesicles
Block the release ofCNS inhibitory
neurotransmitter(GABA)
CNS tetanic spasmsof skeletal muscle
Endotoxins
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)
Fever.Inflammation.
Lowering of blood pressure.
Septic shock
Physiologic Action of Lipopolysaccharide (LPS)
FUNGAL TOXIN
Poison MushroomsMushroom toxins
AmantinCoprineGyromitrinMuscrineOrellanineIbotenic acid
Primary toxicity associated with the Mushroom
Gastrointestinal Nausea, Vomiting, Abdominal Cramping.Disulfiram like effects No symptoms unless alcohol is consumed
with in 2-3 days.Neurotoxic Coma, Convulsion, Excitement, Depression.Cytotoxic Destruction of cells, especially liver and
kideny
MYCOTOXINSAflatoxins (Produced by molds)
Peanuts,corn,wheat,rice,dairy productsASPERGILLUS.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.
Ergolines
Contamination of rye by Calviceps purpurea (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).
ANIMAL TOXINS
SPIDER VENOMWidow spider (lactrodectus spp).NeurotoxicLatrodectism (Pain first at localized at lymph
nodes,Nausea,hypertension,transiet tachycardia, bradycardia,profuse sweating, oliguria, cramps)
Inject venom into skin (0.1mm) 0.002mg
Brown recluse. Cytotoxic Hemolytic 0.48mg/kg LD50
Brazilian wandering.
0.00061-0.00157mg/kg
SCORPIONS2,000 SpeciesNeurotoxinDeath stalker (L.
quinquestriatus)
SCORPIONS
Androctonus Parabuthus Tityus
Hymenopterans
InsectsLocal tissue injurySystemic toxicityAnaphylactic response
LD50
Honey bee (2.8mg/kg)Velvet ant (71mg/kg)Paper wasp (2.4mg/kg)Yellow jacket (3.5mg/kg)Fire ants
(0.66mg/kg)
Box Jellyfish60 tentacles5,000 nematocystsTreatment: vinegar, ice pack
MollusksBlue ringed octopus.Painlessly kill a human with in 5 min.Inject neuromuscular venommaculotoxin and tetrodotoxin.Cone snails.Conus geographus (cigarette snail)
OCTOPUS
ShellfishAmnesic shellfish poisoning.Diarrheic shellfish poisoning.Neurotoxin shellfish poisoning.Paralytic shellfish poisoning.
Amphibians
Poison dart or “poison arrow”100 toxins identified in the skin secretions of
poison dart frogs (Dendrobates & Phyllobates).Phyllobates produce neurotoxin, batrachotoxin.LD50 . 50µgSome toads produce epinephrine,
norepinephrine.
Phyllobates
Dendrobates
Reptiles
3,500 species of snakes worldwide.Venomous snakes fall into six families:ElapidaeHydrophiidaeLaticaudidaeViperidaeColubridaeCrotalidae
Elapidae (cobras, kraits, mambas, coral snakes)
Hydrophiidae (sea snakes)
Laticaudidae (sea kraits)
Viperidae (old world vipers & adders)
Colubridae (bloomslang&keelblack)
Crotalidae(rattlesnakes,water moccasins,copperheads,bushmaster)
Snake venom
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 laticaudidae neurotxic.Snake venom complex mixture.
Snake venom
Protein,peptide,inorganic cations,metals,Lipid,carbohydrates,amines,AA.Enzymes.The typical venom consist of 25 different
enzymes.The most damaging is proteolytic enzyme
(proteases,peptidases,proteinases,hydrolases).
Antivenin
First was described more than 100y ago.Horses, sheep exposed to graduated doses of
venom until become hyper immunizedImmunoglobulin.Animal derived antivenin have potential for
hypersensitivity and anaphylaxis.A cocktail of antivenins can be used against
broad range of venoms.
Antivenin
Venom extractor