The most venomous land snake on earth… Olivier DUBOIS 1

2

Commonly called : The Inland Taipan the Small Scaled Snake Fierce Snake 3

Class: Reptilia Suborder: Serpentes Family: Elapidae Species: Oxyuranus microlepidotus 4

5

Colour : Depanding on seasons, from a rich, dark hue to a brownish olive-green. The darker colour allows the snake to heat itself while only exposing a smaller portion of the body 6

Lenght : Average 1.8 m Up to 2.5 m Eyes : brown iris coloured rim around the pupil 7

Lives in burrows. Eats rodents (mice, rats), birds. Killing method: One single accurate bite, waiting for the prey to die, then returning to safely consume its meal 8

Look at it closer… 9

Do you fear it ? 10

You should because… …its venom is times more toxic than most rattlesnakes and 50 times as toxic as a cobra 11

LD50 (lethal dose 50%) test : Dosing animals with a substance By mouth, by injection or inhalation Test is done when half of the animals in the group have died Indicates the standard toxicity value for a chemical 12

Venom yield for one bite : mg Sub-cutaneous LD mg/kg One bite could cause the death of about 100 human beings. 13

neurotoxic paralysis coagulopathy headache nausea abdominal pain loss of consciousness convulsions 14

neurotoxic paralysis coagulopathy acute renal failure headache nausea abdominal pain loss of consciousness convulsions Myotoxicity Cardiotoxicity Anticoagulant Effects Hemolytic Activity Internal Hemorrhage Edema Inducing Activity Organ or Tissue Damage 15

neurotoxic paralysis coagulopathy acute renal failure headache nausea abdominal pain loss of consciousness convulsions Myotoxicity Cardiotoxicity Anticoagulant Effects Hemolytic Activity Internal Hemorrhage Edema Inducing Activity Organ or Tissue Damage DEATH 16

Taipoxin Paradoxin (neurotoxins) Oxylepitoxin-1 (neurotoxin) … And some phospholipases A2 enzyme (vPLA2s) 17

Participate in : Digestion of prey Venom toxicity (including neurotoxicityn myotoxicity,…) Are natural endogenous ligands (binds to other chemical entities, act as a catalyser) Therapeutics prescriptions : Lipid digestion Host defense mechanisms : inflammation defense Antibacterial defense 18

Receptors, binding proteins for vPLA2s have been identified in mammals (not only in venomous animals !) Do a diversity of mammalian secrete vPLA2s enzyme ? A scientific study shows that sPLA2 fold has been used by both snakes and mammals to generate various proteins with specific biological effects. Snakes and other venomous animals elaborate sPLA2s distinct from those produced by venom glands to support physiological functions 19

Venom glands thought to have evolved from digestive glands A single snake venom… can contain a variety of vPLA2s (up to 15 distinct enzymes) The genes for these vPLA2s are likely to have evolved through positive Darwinian selection. Is this positive Darwinian selection ? 20

Deadly does not mean dangerous ! Is shy and secretive, prefers to escape from trouble, bites only if threatened. 21