Post on 13-Jan-2016
Mammalian Venoms
Charles Norton
Lisa Toelle
Mammalian Venoms
• Of all the diversity of mammals, there are only a few species that exhibit toxicity.
• Although skunks and pangolins emit noxious fumes, they are left out of this report due to there lack of toxicity. They are, however, mild irritants.
Solenodons
• Cuban Solenodon– Solenodon cubanus
• Haitian Solenodon– Solenodon paradoxus
Solenodons
• Characteristics– Resemble large
shrews– Nocturnal– Burrowing– Insectivores
Solenodon Venom
• Mechanism of Action– Channel in second lower incisors to deliver venom– Venomous saliva is delivered from a hollow duct,
which is connected to modified submaxillary salival glands
• Ecological Benefits– Defense– Immobilization of prey
Sources for Solenodon Information
• Folinsbee, K.E, Muller, J. and Reisz, R.R. 2007. Canine grooves: morphology, function, and relevance to venom. Journal of Vertebrate Paleontology 27(2):547–551.
• Zoological Society of London. Retrieved 3-10-09. http://www.edgeofexistence.org/conservation/solenodon.php
• The City College of New York. Retrieved 4-10-09. http://www.culturequest.us/cuba/animallife.htm
Slow Lorises
• Sunda Loris– Nycticebus coucang
• Bengal Slow Loris– Nycticebus
bengalensis
• Pygmy Slow Loris– Nyciticebus pygmaeus
Slow Lorises
• Characteristics– Only toxic primate– Slow-moving
quadrapedal– Nocturnal – Arboreal
Slow Lorises
• Venom Composition– A protein very similar to cat dander
• Mechanism of Action– Venom in saliva (from sebaceous glands near
elbows)– Suck toxin into their mouths for delivery
• Ecological Benefits– Protection from enemies
Sources for Lorises Information
• Krane, S, Itagaki, Y, Nakanishi, K, Weldon, P.J. 2003. “Venom” of the slow loris: sequence similarityof prosimian skin gland protein and Fel d 1 cat allergen. Naturwissenschaften 90:60–62.
• Fry, B. Poisonous Primate?! Retrieved 3-16-2009. Venomdoc. http://www.kingsnake.com/toxinology/loris/slow_loris.html
• National Geographic. (2008). Retrieved 4-10-09. http://news.nationalgeographic.com/news/2007/06/photogalleries/animal-pictures/
• Nature. (2009). Animal Behavior: Slow Food. Retrieved 4-10-09. Nature. http://www.nature.com/nature/journal/v443/n7109/full/ 443248a.html
Shrews
• Northern Short Tailed Shrew– Blarina brevicauda
• Eurasian Water Shrew– Neomys fodiens
Shrews
• Characteristics– Small body– Long nose– Similar appearance to
a mouse or rat
Shrews
Venom Composition– Soricidin– Blarina - BLTX
• kallikrein-like protease capable of cleaving kinins
Shrews
• Mechanisms of Action– Neurotoxic– Paralytic properties in soricidin– Hypotension due to blarina
– Protease activity
Shrew Toxin Mechanisms
NeurotoxicityNeurotoxicityParalysisParalysis HypotensionHypotension
VenomVenom
Impairment of Impairment of Target OrganismTarget Organism
Shrews
• Ecological Benefits– Helps immobilize prey– Defense
• Bite is more toxic if pregnant
– Possible medicinal uses for human pain treatment
Sources for Shrew Information• Kita M, Nakamura Y, Okumura Y, Ohdachi SD, Oba Y, Yoshikuni M, Kido
H, Uemura D. Blarina toxin, a mammalian lethal venom from the short-tailed shrew Blarina brevicauda: Isolation and characterization. Proc Natl Acad Sci USA. 2004 May 18;101(20):7542-7.
• Kita M, Nakamura Y, Okumura Y, Ohdachi SD, Oba Y, Yoshikuni M, Kido H, Uemura D. Purification and characterisation of blarinasin, a new tissue kallikrein-like protease from the short-tailed shrew Blarina brevicauda: comparative studies with blarina toxin. Biological Chemistry. February 2005, Vol. 386 Issue 2, p177-182
• Gonthier, Gilles. (2009). Retrieved 4-10-09. http://www.wildlifenorthamerica.com/Mammal/Northern-Short-tailed-Shrew/Blarina/brevicauda.html
• Biology Department, Davidson College. (1999). Retrieved 4-10-09. http://www.bio.davidson.edu/Courses/anphys/1999/Rachal/rachal2.htm
Platypus
• Ornithorhycnus anatinus
• Characteristics:– Electro-sensitive– Semi-aquatic– Mostly nocturnal– Only venomous
mammal in Australia
Platypus
• Venom Composition– Defensin-like proteins (three of which are unique to
platypuses)– Made in glands in the legs– Evolved via gene duplication of immune system
genes
Platypus
• Mechanisms of action:– Leads to edema around the area of the wound and
increases the victims sensitivity to pain.– May also result in decreased blood pressure,
respiratory distress, and slightly hemolytic– Neurological effects
• Linked to decrease in pH leading to altered ion entry
Platypus Venom
NeurologicalNeurologicalEffectsEffects
CardiovascularCardiovascularEffectsEffects
Local Edema Local Edema and Painand Pain
VenomVenom
Impairment of Impairment of Target OrganismTarget Organism
Platypus Spurs
– Delivered via spurs on hind limbs of males – Only mammals to squirt venom (not mixed
with saliva)
Spur
Platypus Video
• http://www.bbc.co.uk/mediaselector/check/nature/animals/mammals/up_close/video/ovt_platypus?size=16x9&bgc=273824&nbram=1&bbram=1
Click on Hyperlink to View Video
Platypus
• Ecological Benefits– For dominance during mating season
• only found in males
– Defense– Possible uses for medicinal research in pain
in humans
Platypus Sources
• Geristen V. Platypus poison. Protein Spotlight: Issue 29, 2002.
• Plater G, Milburn P, Martin R. Venom From the Platypus, Ornithorhynchus anatinus, Induces a Calcium-Dependent Current in Cultured Dorsal Root Ganglion Cells. J Neurophysiol 85:1340-1345, 2001.
• Luna Media Pty Ltd. (2007). Evolution of Platypus Venom Revealed. Retrieved 3-26-09. Cosmos Magazine. www.cosmosmagazine.com/news/1423/evolution-platypus-venom-revealed
• Fry, B. Platypus Venom. Retreived 3-16-2009. Venomdoc. www.kingsnake.com/toxinology/old/mammals/platypus
Summary
• Few mammals posses toxins
• The diverse mammalian clades possessing toxins suggest independent evolution.
• Toxins found in these mammals appear to be primarily for defensive purposes