After four years of work and over $150,000 in grant money, the big paper examining the diversification of the venom system in the Anguimorpha lizards has finally been published 
Fry BG, Winter K, Norman JA, Roelants K, Nabuurs RJA, van Osch MJP,
Teeuwisse WM, van der Weerd L, Mcnaughtan JE, Kwok HF, Scheib H,
Kochva E, Miller LJ, Gao F, Karas J, Scanlon D, Lin F, Griesman L, C
Shaw, Wong L, Kuruppu S, Hodgson WC (2010) Functional and structural
diversification of the Anguimorpha lizard venom system Molecular and
Cellular Proteomics 9(11):2369-90
www.venomdoc.com/venomdoc/Scientific_publications_files/2010_Fry_Anguimorpha_venom_system.pdf
At every opportunity we have gone to great pains to stress that anguimorph lizards are of but of trivial direct medical importance to humans (with the exception of helodermatids and of course the komodo dragon). We have however also stressed that this disappearing biodiversity is a tremendous bioresource with tremendous potential for use in drug design and development. As illustrated that in addition to new isoforms of previously known toxin types, we discovered five entirely new toxin classes, three of which have potent hypotensive actions upon the vascular system and thus have significant potential for use in drug design and development.
A representative news report showing the attitude we are taking in communicating the results is:
www.australiangeographic.com.au/journal/lizard-venom-may-treat-heart-disease.htm
This group of lizards have been fascinating to study,both in the field and the lab. The anguimorphs have a combined arsenal system employing teeth and venom, with virtually infinite variations due to the evolutionary tinkering that has gone on during 130 million years of evolution within this clade. Helodermatids are one extreme, relying just on the venom for prey capture, with the deeply grooved gracile teeth restricted to a venom delivering role. In contrast, komodos have the large serrated teeth as the primary weapon, using a grip-and-rip strategy to inflict deep parallel wounds. Mechanical damage that in some cases results in very rapid death from blood loss (eg slicing the femoral artery). The role of the venom is to exaggerate the blood loss and shock inducing mechanical damage caused by the bite. We have identified two main actions common to all anguimorph venoms: anticoagulation and hypotension. Enough loss of blood would lead to a drop in blood pressure sufficient to induce shock or unconsciousness. So anticoagulant toxins facilitate a steady march in this direction. Similarly,hypotensive toxins accelerate the unconscious endpoint.
Komodos evolved not in Indonesia but in Australia, and were not the biggest to have roamed, at least two larger varanids existed to predate on megafauna. The second largest radiated to Timor while komodo radiated to Flores and nearby islands. The modern day situation is that the komodos have three mammalian potential prey choices. All of which are feral. The introduced pigs and deer are within the natural prey size (40-50 kg) while the buffalo are dramatically larger than would have been a reasonable size for komodos to kill and also occupy an ecology unlike anything in Australia.
These collective differences are starkly reflected in attack success. Attacks on pigs and deer are extremely successful. About three quarters bleed out within the first thirty minutes and another approximately fifteen percent succumb within three or four hours. Repeated attacks by the same or other komodos is not uncommon. In dramatic contrast is the outcome of attacks on water buffalo. Which invariably get away, with deep wounds to the legs. Upon which they go and stand in feces filled watering holes. Creating a perfect scenario for dramatic infections. Not from the dragons mouth, but rather having an environmental source. Deep wounds in feces laden water is a perfect scenario for the flourishing of bacteria, particularly the nasty anaerobic types. Thus, the sampling of komodo mouths that purported to show them harbouring pathogenic bacteria neglected to sample the real source of any infection to the water buffalo: the faeces filled waiting hole the dragons recently drank from. It has been a man made artificial scenario all along that has nothing to do with the evolution of the predatory ecology of komodos.
Having gotten septicaemia in Flores from deep lacerations resulting from a boating mishap in Flores harbour (water that is pretty disgusting) I can attest to how quickly such environmental sources can produce life threatening infections. As a consequence of the Flores doctor doing a shockingly inept job of cleaning up the wounds before stitching them up, I ended up delerious and near unconscious in the Bali International SOS clinic 36 hours later getting emergency IV antibiotics.
There is nothing special about komodos. They are simply the largest extant species of a clade that had two extinct larger species and has two other extant species (V. varius and V. salvadorii), all of which share the unique large,blade like serrated teeth. None of which have ever had the slightest whiff of using bacteria as a weapon.
Cheers
B
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Dr. Bryan Grieg Fry
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Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
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http://www.venomdoc.com
