Thursday, 29 May 2014

Good Old Venom



The collection of snake venom has been a practice for over 80 years. Old school venom extractions where collected from wild snake populations. These samples were being collected in the hope to produce an antivenin and potentially save thousands of lives in the future. This was a very dangerous job, when a bite was more than often fatal. This was a time of real scientists and reptile enthusiast who put their life on the line for the benefit of scientific breakthroughs. Some of the samples collected were stored away 80 years and had not seen the light of day until now.

 Roy Mackay, Neville Goddard and Kevin Budden
Live Taipan Expedition Cairns 1949

While Brian Fry was going through an old store room he discovered and old box which contained a priceless tressure, 80 year old snake venom samples. These vials contain venom form mostly Acanthophis, Notechis, Oxyuranus and Pseudechis species. These samples where particularly valuable as some of the Notechis samples where from threatened island populations which are currently in decline. Venom from these populations have been rarely collected in the last 50 to 80 years. One sample carried the memory of Kevin Budden who died in 1950 following a Coastal Taipan bite. The sample was from the first Coastal Taipan collected for antivenin production and the same animal that took Kevin Budden's life.

 Bill Haast with a King Cobra
Source: http://billhaast.com/photo_gallery.html
29/05/14 18:00
A study was conducted to compare the old freeze dried sample with newly collected samples to determine if the vintage venom proteins were still intact and if they were still active after all this time. The results showed that the vintage venom was only slightly less potent than the freshly collected samples. Over time there had been some changes in a couple of the protein structures which means that these vintage samples would not be ideal for the production of antivenins. However, these samples remain a valuable resource for venom evolutionary studies as these are the only samples currently at researcher’s disposal.

 Bill Haast, Venom extraction, African Puff Adder
Photograph By Bill Anderson

This discovery also opens the door to new venom storage techniques, which could potentially change the way collection of venom is practiced. This is important when considering rare and endangered species. The ability to store venom for a long period of time means less disturbances and pressures on delicate ecosystems as less individuals are required for research. This understanding of venom shelf life means that new discoveries may continue in the unfortunate event that threatened species disappear along with their secrets.

References:

Jesupret, C., Baumann, K., Jackson, T. N., Ali, S. A., Yang, D. C., Greisman, L., ... & Fry, B. G. (2014). Vintage Venoms: Proteomic And Pharmacological Stability Of Snake Venoms Stored For Up To Eight Decades. Journal of proteomics.



Monday, 26 May 2014

Eight Legged Freaks



Not many people are very fond of spiders, they are usually seen as horrid vermin and always an uninvited guest in thousands of homes around Australia. However spider are very effective, deadly predators. They are the pioneers of trapping and ambushing prey which in some cases can be ten time the size and weight of the spider. Arachnids have been around for the last 300 million years. They come in all shames and sizes from species the size of a pin head to the goliath bird eater (Theraphosa blondi) growing up to 30cm across. Australia has its fair share of spiders with over 2,500 species but there is one in particular which is most notorious throughout the country; the Sydney funnel web (Atrax robustus).

M Gray © Australian Museum


Atrax robustus
M Gray © Australian Museum
 Photo by M.Gray at the Australian Museum 

M Gray © Australian Museum
 This extremely dangerous spider is considered one of the most toxic in the arachnid kingdom and has resulted in 14 human fatalities prior to the production of anti-venom in 1981. There are two lethal neurotoxins which have been isolated from the venom of this spider they are a robustoxin and the versutoxin. The effects from a bite can become very server in a short amount of time (Szeto et.al 2000).

 Photo by Sam Rutty  
Generally people come into contact with male spiders as they travel across the landscape in search of a female. It is the male which carries the most toxic venom possibly due to a defensive evolutionary responses as the male are vulnerable to other predators during this time. Females do not leave their burrows and therefor face less chance of predation. Female bites are still extremely painful and can lead to some unpleasant effects but are not fatal. This is due to the lower levels robustoxin in the female’s venom (Graham et.al 1997). Robustoxin effects the neuromuscular junction, immediately disturbing respiration, blood pressure and causing server hypotension (Mylecharane et.al 1989).

                                                                   Atrax robustus                               
                                                         Male (left) and Memale (right) 
                                       Photograph courtesy of Australian Venom Research Unit

Whatever your view of these beautiful spiders, it is impossible to deny the chemical wonders that reside in their little exoskeletons. The potential pharmaceutical benefits of their venom is still being explored however research continues in the hope that in the near future we will harness the power of venom.   


References:
Mylecharane, E. J., Spence, I., Sheumack, D. D., Claassens, R., & Howden, M. E. (1989). Actions of robustoxin, a neurotoxic polypeptide from the venom of the male funnel-web spider (Atrax robustus), in anaesthetized monkeys. Toxicon, 27(4), 481-492.

Nicholson, G. M., Walsh, R., Little, M. J., & Tyler, M. I. (1998). Characterisation of the effects of robustoxin, the lethal neurotoxin from the Sydney funnel-web spider Atrax robustus, on sodium channel activation and inactivation. Pflügers Archiv, 436(1), 117-126.

Szeto, T. H., Wang, X. H., Smith, R., Connor, M., Christie, M. J., Nicholson, G. M., & King, G. F. (2000). Isolation of a funnel-web spider polypeptide with homology to mamba intestinal toxin 1 and the embryonic head inducer Dickkopf-1. Toxicon, 38(3), 429-442.

Friday, 2 May 2014

Death and Destruction

In my last blog I touched on death adder venom and its effects on the human body. This post will go into more detail about the types of venom, their effects and the processes involved in revering these deadly toxins. Although there will be examples of the species which carry a particular venom it is important to remember that venoms will contain more than one toxin.  

WARNING: I will post juicy pictures so if you are squeamish then maybe find another post to read this week.


Neurotoxic venom attacks the neuromuscular junction which causes paralysis of the voluntary muscles. Without treatment death can occur, caused by asphyxiation and respiratory failure. Other symptoms include slurred speech loss of vision, sweating, convulsions and episodes of unconsciousness. Many elapid venoms display highly neurotoxic side effects. Tiger snakes, Brown snakes, taipans and adders are some examples of Australian species with highly neurotoxic venom. Treatment for this is in the form of antivenin. Tiger snake antivenin is commonly used for a wide range of elapid species.
Rough scale snake bite
http://www.brisbanetimes.com.au/queensland/reptile-handler-bitten-by-pet-snake-denies-being-reckless-20140116-30w8v.html
29/4/14 20:46
Haemotoxins destroy red blood cells causing huge problems for the circulatory system. Internal bleeding and hemoraging also leads to multiple organ failure the victim may experience bruising at the bite site. Clotting of the blood is common as well as anticoagulant properties in some species. Some cases have reported victims uncontrollably bleeding from all of the body’s orifices. Antivenin can reversed some of these effects if medical attention is received shortly after a bite however amputation of effected digits or limbs is common in poorer countries where victims may not receive treatment for a couple of hours. Many viper species possess this venom as well as the black snake family here in Australia. Gaboon viper and the Eastern diamondback rattlesnakes are some of the most common cases.

Fasciotomy procedure. An attempt to relieve the massive swelling from Eastern Diamondback Rattlesnake bite. Not commonly practiced to to risk of infections and terrible scaring.
http://www.ebaumsworld.com/pictures/view/31375/
29/4/14 20:19
Cytotoxins are similar to hemotoxins however they are much more destructive at the bite site. They destroy cellular tissues and cause blood poisoning. Its is advised not to apply a pressure bandage as venom attacks the bite site so withholding it can cause more damage. Puff adders, Black mambas and African cobras commonly posses a cytotoxic venom as well as a strong neurotoxin.
Puff adder bite
http://www.capesnakes.org.za/forum/viewtopic.php?f=46&t=565
29/04/14 20:39
Myotoxins are a gruesome set of toxins which destroys muscle tissues. These toxins block the signals to the muscles and cause then to degenerate. Symptoms consist of numbness of the limbs, swelling of the tongue, painful breathing and at later stages necrosis of the limbs. Liver failure is common as the organ works overtime to rid the body of toxins created by the festering wound. The Fer de lance  of South America is well known for having a myotoxic venom.
Severe necrosis following a Fer de lance bite.
http://www.squidoo.com/dangerous-snakes-of-latin-america
29/04/14 19:58
Again it is important to remember that it is not as clean cut as this. Lots of species produce a cocktail of toxins which may leave the victim feeling a number of these effects. It can also depend on the individual bitten. Some people may handle venom better than others. There are cases of people going into anaphylactic shock and dying minutes after a bite. It’s probably best never to find out.

References:
Mirtschin, P, Davis, R 1992, Revised edition dangerous snakes of Australia, an illustrated guide to Australia's most venomous snakes, New Holland Publishers Ltd, UK.

Teixeira, C, Landucci, E, Antunes, E, Chacur, M, Cury, Y 2003,” Inflammatory effects of snake venom myotoxic phospholipases a2, Toxicon, vol.42, iss.8, pp.947-962. 

Monday, 28 April 2014

Adding It Up

Australia is home to some of the world’s most beautiful and deadly snakes.  There are currently 93 Species of Elapid in Australia. Elapids are classified usually by their short fixed fangs at the front of their mouth. Elapids are a extremely diverse group of snakes. Ranging from the nitrious 5 meter King cobra (Ophiophagus hannah) found in India, to the 40cm Small eyed snake (Rhinoplocephalus nigrescens) found on the east coast of Australia. Most of which are found here in Australia are long, slender, extremely fast moving and very alert snakes. Remaining active during the day moving constantly to find food. However there is a Genus of Elapid which is slightly unique in their appearance and behavior, these are the Acanthophis species or death adders.  There are currently 4 species of death adder in Australia along with a small number of other species found in Papa New Guinea. 
Photo by Ryan Pilgrim
Pilbara Death Adder
Acanthophis wellsi


Death adders belong to the Elapid family however at first glance they would appear to be more at home with the Vipers. They resemble the European adders, Puff adders and other viper species, they are short stout snakes not well adapted for traveling long distances in search of food but instead have evolved to become effective ambush predators. Death adders will bury themselves in the leaf litter or sand and wait patiently for prey to come to them. There have evolved a lure at the end of the tail which they leave exposed and wriggling in order to entice a small animal closer. They possess a lightning fast strike which has been measured at 0.2 of second from a standing ambush position to the target. This tactic of sit and wait in ambush is common throughout the viper family and a number of species which also use this caudal luring technique to attract prey.
Puff Adder
 Bitis arietans
http://www.venomousreptiles.org/classifieds/detail/12133
28/4/14 18:37 
 Photo by Ryan Pilgrim
Common Death Adder
Acanthophis  antarcticus
It is clear that this is an excellent example of convergent evolution at work. There are no vipers in Australia, this indicated the death adders have independently evolved this style of prey capture alongside vipers found all across the globe. Death adders produce a neurotoxic venom which can affect the nervous system and symptoms relate to neuromuscular failure leading to paralysis and breathing failure. This is where the similarities end as vipers possess a haemotoxic venom which attacks red blood cells either causing serious haemorrhaging or clotting of the blood this causes multiple organ failure and commonly necrosis at the bit site.


 Photo by Ryan Pilgrim
Albino Northern Death Adder
 Acanthophis praelongus
 References:

Shine, R 1980, “Ecology of the Australian death adder Acanthophis antarcticus (elapidae): evidence for convergence with the viperidae”, Herpetological, vol. 36, iss. 4, pp.281-289.