Natural toxins: Part 1 (Proceedings)


Natural toxins: Part 1 (Proceedings)

Aug 01, 2010

Poisonous animals – Tissue is toxic; Poisoning through ingestion; Concentration differences in portions of the body – toxicity

Venomous animals – gland or glands which produces the venom and a Connecting system between gland and delivery apparatus.

Venom delivery is not "all or nothing", but rather is graded and their purposes are 1).

Capture and digestion of food, and 2). Offers protection against predators

Toxicity of venom and poison

The LD50 for any particular venom will vary, depending on:
     - The type of animal it is tested in
     - The route of injection
     - The way the venom is prepared for injection
     - Variability in both toxicity and composition of venom, both within a single animal, between animals of the same species

Properties of animal toxins

     - Complex chemistry
     - Proteins (Polypeptides, enzymes)
     - Small molecules ( Serotonin, Lipids, amines)
     - Carbohydrates
     - Metals (Magnesium, calcium, and zinc are the most prevalent metals, copper has been detected in some venoms - lethality role??)
     - Modified saliva

Venomous snakes

     - Ectothermic reptiles
     - There are at least 3,000 species of snakes (375 species danger to man; five (5) confirmed families

Pit Vipers (Crotalidae)

     - Pit vipers (e.g., rattlesnakes, cottonmouth, moccasin, and copperhead).
     - Viperine snakes have long, hinged, hollow fangs; they strike, inject venom (a voluntary action), and withdraw.
     - Many bites by vipers reportedly do not result in injection of substantial quantities of venom
     - Viperine venom is typicaly hemotoxic, necrotizing, and anticoagulant
     - Neurotoxic components are present in the venom of some species. Mojave rattlesnake (Crotalus scutulatus).

Elapine Snakes (Cobra, mamba, and coral snakes)

     - short fangs and tend to hang on and "chew" venom into their victims
     - venom is neurotoxic and paralyzes the respiratory center

Snake Bite incidence

     - Veterinary (Unknown; active humoral immunity can occur if multiple bites occur)
     - Humans (Approximately 7500 reptile bites (2001) AAPCC report. Rattlesnakes are primarily implicated.

Poisonous snakes

Species of poisonous snakes found in North Carolina - Pit Vipers (Copperhead (Agkistrodon contortrix), Cottonmouth (Agkistrodon piscivorous. Timber Rattlesnake (Crotalus horridus, Eastern diamondback rattlesnake (Crotalus adamanteus, Pygmy rattlesnake (Sistrurus miliarius), Elapidae Eastern coral snake (Micrurus fulvius fulvius)

Rattlesnake venom

     - Composition (Digestive enzymes, Spreading factors (hyaluronidases), Proteases, DNAses, RNAses)

Snake bites

Snakebite, with envenomation, is a true emergency ("Dry bites" account for ~ 50% of all bites). Rapid examination and appropriate treatment – essential. Keep the animal quiet and limit its activity