Reptile & Amphibian Forums

OK, so I am reading as much as I can. I ran across a Wikapedia talking about the Lace monitor, Perantie and the spotted tree monitor, saying if it bites it shows the same signs.

Is this true.
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Doubtful! Wikipedia is a faulty source.... Any anus can type what they want in there. Further the search and see what you come up with.

There have been venom proteins found in monitors as well as others lizards. They may not be as potent as snakes but they are there. If i remeber right and this may be wrong they where found in bearded dragons and even iguanids. Ian

No way!

Seriously?

Scientifically speaking Yes, many monitors, iguanids etc do appear to have specialised glands similar to the Duvernoy's gland in some snakes that do produce a venom.

Clinically speaking they are as non-venomous as they always were.

Plain English says they are non-venomous.

What I'm saying is that the technical/scientific definition of venom applies to these lizards. However, in application they are as non-venomous as anything else.

Cheers,
Terry
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It's what you learn AFTER you know it all that counts!

Terry Phillip
Curator of Reptiles
Black Hills Reptile Gardens
Rapid City, SD.

www.reptilegardens.com

Anyone that has had a good bite from a monitor knows that there is more going on than just teeth. It bleeds and hurts more than it should. Tyler.

http://www.abc.net.au/science/news/stories/s1506321.htm

http://ezinearticles.com/?Rainforest-Animals---Lace-Monitor&id=1073048

http://www.abc.net.au/rn/science/ss/stories/s1520986.htm

http://www.aad.gov.au/default.asp?casid=34728

http://www.livescience.com/animals/051117_lizard_venom.html
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www.frogfreaks.com

The presence of venom does infact make them venomous. To what degree should be the question. Its not so much the venom but how it is delivered in the case of lizards that decides its potecty. Lizards just cant put all the venom at one point at one time like say an adder can. I have been bit on many ocasiones by one of the most potent monitors v.griseus and I have never felt light headed or suffered any ill efects other than a heightened level of pain. Just a thought. Ian

Not long after the paper describing these glands and their products was published I got an email from a school teacher in Bangladesh who, for many years, had been telling poeple that monitor lizards did not have a "poisonous" bite and therefore shouldn't be killed on sight. When he read the sensationalist publicity that accompanied the publication he thought maybe he had been mistaken.
Technically you could argue that monitor lizards should be classed as venomous because they possess primitive glands that secrete very low concentrations of proteins. But for all practical purposes (clinical, legal, husbandry, ecological) they are not venomous animals. My delight at the publication of this paper was quickly extinguished by the flood of nonsense that accompanied it. If you tell people in uneducated communities that an animal is venomous they will no longer tolorate them and probably go to great lengths to kill as many of them as possible.
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Mampam Conservation

I'm glad you brought this point up. There is no useful sense calling them venomous. The publicity behind could be compared a "tabloid".

By the way Daniel I was curious to know if you were using genetic markers for your fecal analysis in your studies?

Cheers,
Jason
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"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

There is no useful sense calling them venomous. The publicity behind could be compared a "tabloid".

Most stuff you read in the tabs is BS, this is actual fact. If they're working on drugs, using 'the venom from varanids' (aren't they using Gilas to help type2 diabetics and don't Gilas/Beadeds have almost the same venom as varanids?)How can they 'not' be classified as venomous, even though 'not dangerous?

If on a list of the most venomous animals, let's say the King Cobra is near the top of the list.
Varanids would be near the bottom of the list, but they would still be on the list. Better the truth be available in full, than keeping it hush hush, in case people get the wrong impression. The question, "are monitors venomous" or, 'do they have venom', seems to be posted on a regular basis, so there must be a lot of curiosity about the subject. This thread has answered a lot of questions I had. If what you're saying is, they shouldn't be called venomous, would your answer to the original poster's question have been "No"?

Susan.

Hi Susan,
The argument is really over a definition, and it is an old argument. I do not agree that pharmacological properties alone constitute venom as Dr. Fry does. For something to be considered venom the animal that possesses it needs more than a cocktail of toxins in its mouth. For example a rattlesnake is fully equip with the "machinery" to deliver under high pressure a dose of venom specifically to kill its prey. There are specific skeletal musculature, highly kinetic skulls for fang placement, a ready reserve of venom, specific predatory behavior that fits a venomous lifestyle and more.
The mere presence of the toxin does not constitute venom as defined in the literature. It has been mentioned time and time again that human bites will cause adverse pharmacological effects. Does that make humans venomous?
So I do not believe that these toxins are used specifically for killing their prey and that is why I don't consider them venom. It is really that simple.
They have some other function and that function is largely unknown. To group these systems together masks their true role.
Brian claims that a neurotoxin can have no other role. I disagree with that as well.
Cheers,
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"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

Hi Jason, I see your point and I see Bryan's point. I appreciate your response to my post and look forward to more discussions between the two of you. As you said, "it's great stuff"!

Thanks,
Susan.

>>The mere presence of the toxin does not constitute venom as defined in the literature.

Actually that is precisely the definition as long as it is combined with a mechanism for delivery (otherwise it'd be a poison if it was delivered by ingestion or absorption). In this case it is teeth. The internal anatomy of the gland shares significant similarities with that of the helodermatid lizards. You cannot arbitrarily split hairs and lable one veomous but not the other. Science does not work that way. If the same gland and the same chemical arsenal is a venom in one, it is a venom in the other. The difference in tooth structure is reflective of difference in prey: large and robust for varanids, smaller and less dangerous for helodermatids.

Intricate systems such as found in viperids are the epitome, not the beginning.

> It has been mentioned time and time again that human bites will cause adverse pharmacological effects. Does that make humans venomous?

No because those are bacterial infections not from mutated proteins, as we covered in a similar thread a couple years ago when you trotted out the same red herring.

>>So I do not believe that these toxins are used specifically for killing their prey and that is why I don't consider them venom. It is really that simple.

So killing of prey capture is the sole definition of venomous? That is a very weak argument.

All of our evidence is pointing towards a role in prey capture in conjunction with the very large wounds produced by the teeth. This is not to say a defensive aspect may not be present too. However, as we are seeing a consistent pattern of robustness in those that predate on vertebrates versus those that predate on invertebrates, this does support prey capture roles.

Cheers
B
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Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

In this case it is teeth

Are there any other venomous animals other than heloderms and varanids, that deliver their venom without using fangs, stingers, barbs etc?

Also, I am curious to know, if Dobry thinks heloderms should also 'not' be classed as venomous, since you say, they have basically the same method of delivery as varanids and if he does think they are actually venomous, what differentiates them from varanids?

I'm trying to figure out if this whole disagreement is based on a preference not to 'label', rather than actual facts.

Thanks,

Susan.

>>Are there any other venomous animals other than heloderms and varanids, that deliver their venom without using fangs, stingers, barbs etc?

Octopuses do it by drilling a shell with the radula and then squirting the venom in or biting into an non-hard shelled animal (e.g. shrimp or soft part of the leg joints of crab) with the beak and chewing it in.

Some of the basal Conoidae snails (e.g. mitres and turrids) have only rudimentary harpoons or even just slightly modified radula relative to the extremely advanced delivery architecture of the Conus genus.

This is the same sort of variation of a theme as seen in snakes or lizards as well as fish. In the fish, the basal fish was a venomous cartilaginous fish. Primative sharks like Port Jackson sharks retain the venomous spines while the rest of the sharks have secondarily lost it. The stingrays of course have extremely diverisified the venom system into a very effective delivery system. The third major cartilaginous lineage, Chimeraformes, have also enlarged the spines and increased not only the amount of venomous tissue but also the relative efficienty of delivery. The bony fish perpetuated this, as seen in catfish and stonefish. The rayfin fish (goldfish, tuna, salmon etc) have secondarily lost the venom on multiple occasions.

>>
>>Also, I am curious to know, if Dobry thinks heloderms should also 'not' be classed as venomous, since you say, they have basically the same method of delivery as varanids and if he does think they are actually venomous, what differentiates them from varanids?

He is basically basing it on human effects. Which is evolutionariy irrelevant.

>>
>>I'm trying to figure out if this whole disagreement is based on a preference not to 'label', rather than actual facts.
>>

I do think that is it. I can understand and do appreciate where he is coming from, due to the negative societal implications of an animal being 'venomous' but that is irrelevant to the science.

Cheers
B
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Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

I can understand and do appreciate where he is coming from, due to the negative societal implications of an animal being 'venomous' but that is irrelevant to the science.

Yes, I feel the same way. Thank you for answering my many questions so well! (I have a few more....)

Are varanids commonly thought of as venomous in Aus? If so, has it impacted the wild population, or the public's perception of them?

Is that whole 'bacteria spiked, dragon saliva' just a smoke screen and could it be the dragon's venom that's pre-digesting the prey?

Are scientists trying to change their classification to 'venomous' and that's what has the conservationists up in arms? Or, is it more like, if we don't talk about it, maybe it will go away?

Thanks,
Susan.

>>
>> Are varanids commonly thought of as venomous in Aus? If so, has it impacted the wild population, or the public's perception of them?

Some aborigines have certainly thought of 'something' going on as have some of the SE Asia locals.

As for more recent developments, venomous animals in Australia are not demonised like they are in much of the rest of the world.....probably because pretty much everything is venomous here!!!

>>
>>Is that whole 'bacteria spiked, dragon saliva' just a smoke screen and could it be the dragon's venom that's pre-digesting the prey?
>>

*perhaps* but I'd need to get a bit more info of exactly what that study showed and also if controls (like bacteria containing saliva from a dogs mouth) were used.

>>Are scientists trying to change their classification to 'venomous' and that's what has the conservationists up in arms?

Its really a difference between scientifically venomous and venomous from the human medical perspective. Very different approaches, theoretical vs practical. I consider varanids venomous from a technical perspective but do not consider them as venomous from a legal-medical perspective.

>Or, is it more like, if we don't talk about it, maybe it will go away?

Like global warming

Cheers
B
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Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

>He is basically basing it on human effects. Which is evolutionariy irrelevant.

No Sir! This is what you have done!

2002. Kardong, K. V. 2002. Colubrid snakes and Duvernoy’s “venom” glands. J. Toxicol.—Toxin Rev. 21(1): 1-15.

The complete paper can be downloaded here for free for those intersted:
http://www.wsu.edu/~kkardong/Web of KVK_06b/Publications/References.htm

Cheers,
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"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

No it isn't useful. It's very interesting from an evolutionary perspective but thats as far as it goes. From the point of view of conservation it's about the worst label they could have. And yes the publicity surrounding it was very tabloid like and completely irresponsible. I suspect it will also play a part in future legislation regarding keeping monitor lizards in captivity.

We have never had the money to look for DNA in samples. Until last year we didn't have the facilities to store fresh samples properly.
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Mampam Conservation

If you are interested in pursuing any of these methods I would be glad to help you. I have a method of storing blood samples at room temp for months without any degradation. I imagine It could work with other types of samples as well.
Cheers,
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"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

As noted by other replies, yes they are venomous but this is from a technical, evolutionary perspective not from a practical perspective. Having had my hand destroyed by a Varanus varius, which despite two surgeries will never be the same incuding the distal segment of the index finger being permanently numb from sliced nerves, I'd be more concerned about the teeth!

This isn't to say that it doesnt have a role in the natural capture of prey but those sorts of bites are different than the typical defensive slash typically inflicted onto keepers. Like rear-fanged snakes, they have to hang on and give a good chew to get things in properly. Symptomatic human bites are typically localised pain, swelling and bleeding but I have documented cases of system wide muscle pain and nausea.

This is a good example of the true beauty of science, its amazing what can be found when someone actually takes the time to look!

All of that stuff about toxic bacteria is scientific voodoo. Last time I looked in a komodos mouth, the teeth were white and shiny and the gums pink and clean. There is no rotting prey item flesh to be found. All monitors are actually quite clean animals and will lick lip as well as rub the head leaf litter repeatedly after a meal to get rid of the gore.

In Auffenbergs 1981 one book, the only source of this hypothesis, early in the book he basically sees a deer with a hang-nail. Thats it. No documentation of a komodo following it for days. Nothing. Nada. Zip. Yet towards the end of the book he states a strong causitive association between septicemia and prey capture. But no data in-between supporting it.

However in his own book there is data in beween contradicting the bacteria hypothesis. Such as his own studies showing komodos prefer live prey over fresh kills and both way preferred over carrion. In otherwords, they will eat rotting food if nothing else is around. But a decomposing goat staked out for a Nat Geo documentary is hardly natural behaviour. Also, his own observations showed the same lip licking/head rubbing behaviour that can be readily observed in other varanids. Further, when he staked out live goats for Komodos to tear into, he noted that the goats quickly became unusually 'quiet' and seemed to rapidly go into shock after being chewed on for a bit. Hmmmmmmmmmmm

Cheers
B
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Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

In Auffenbergs 1981 one book, the only source of this hypothesis,

I just recently saw a documentary, showing biologists taking samples of saliva from trapped dragons and analysis showed there to be several different types of bacteria present.

Do you think that could just be normal bacteria found in the mouth?

A different documentary shows the application of known dragon saliva to a peice of raw meat (deer?), with an untreated piece of meat, side by side with time lapse photos showing the treated piece putrify at an alarming rate, compared to the untreated meat. It looked like acid ate it away, while the other piece hardly changed. Could venom do that?
Have there been any studies on carcasses taken from dragons, to see if there were traces of venom in the bloodstream?
How is the venom delivered? Could it be carried by the saliva?

Thanks.

Susan.

>>In Auffenbergs 1981 one book, the only source of this hypothesis,
>>
>>I just recently saw a documentary, showing biologists taking samples of saliva from trapped dragons and analysis showed there to be several different types of bacteria present.
>>
>>Do you think that could just be normal bacteria found in the mouth?
>>

The bacteriology of oral saliva and gum line swabs taken from Komodo dragons has been previously reported by Montgomery et al 2002. They note a marked difference in the number and type of isolates found in wild and captive animals. These authors do not report any semi-quantitative results to identify the bacterial burden that was found, nor do they attempt to correlate the flora found with the diet/prey of the individual animals. The captive animals had a smaller variety of isolates reported with a predominance of coagulase negative Staphylococcus species that are unlikely pathogens. In 26 wild Komodo dragons, they note eight isolates of Staphylococcus aureus, a rare and unusual isolate of any animals' oral flora, as well as two isolates of Pasteurella multocida, which is not typical reptile flora. P multocida has been isolated from a variety of mammals and in one patient after a Tasmanian devil bite but have not been isolated from reptiles. In order to support the pathogenicity of Komodo dragon oral flora, Montgomery et al injected 10 mice with saliva samples from five wild animals, only one of which contained P. multocida, intraperitoneally and noted some lethality but could not correlate it with the bacteriology of the injected specimens. In addition, they did not culture the peritoneal cavity of the mice. It is likely that the P. multocida isolated from the two komodos was from the flora of a recently eaten prey animal, not resident in the mouth itself.

If one looks at other reptiles to extrapolate Montgomery et al.’s findings, it seems that rattlesnake bites are similar in that their wounds also had been thought to be at high risk of secondary infection from the bacteria harboured in the rattlesnake venom. However, this is not the case. Rattlesnake bites rarely get infected unless there is severe envenomation in which case the necrotic tissue would be at risk from opportunistic infection rather than infection being caused by delivered bactria. Goldstein et al. in 1979 demonstrated that venom itself was sterile and that the bacteriology of the oral cavity of the rattlesnake was reflective of the fecal flora of its prey. They cultured three cases of fresh snakebite wounds and found only rare human skin isolates. They further studied the in vitro activity of venom and found that it possessed generalized antibacterial activity. Goldstein et al. in 1981 also studied the development of normal flora in captive garter snakes and found that coagulase-negative staphylococci were the most frequent isolates and that there was a plethora of organisms but no Pasteurella multocida. In non-reptilian bite infections, P. multocida and many other bacteria are typically recovered from cultures of infected dog and cat-bites that do not result in mortality for the victims (Talan et al 1991).

Thus, evidence for a primary role of toxic bacteria in debilitating and ultimately killing Komodo Dragon prey remains entirely speculative

- Montgomery JM, Gillespie D, Sastrawan P, Fredeking TM, Stewart GL. Aerobic salivary bacteria in wild and captive Komodo dragons. J Wildl Dis. 2002 Jul;38(3):545-51.
- Goldstein EJC, EO Agyare, AE Vagvolgyi, M Halpern. Aerobic Bacterial Oral Flora of Garter Snakes: Development of Normal Flora and Pathogenic Potential for Snakes and Humans. Journal Clinical Microbiology 13:954-6,1981.
- Goldstein EJC, DM Citron, H Gonzalez, FE Russell, SM Finegold. Bacteriology of Rattlesnake Venom and Implications for Therapy. Journal Infectious Diseases 140:818-21,1979.
- Talan, DA, DM Citron, B Singer, P Froman, GD Overturf, EJC Goldstein. Antibacterial activity of crotalid venoms against oral snake flora and other clinical bacteria. Journal Infectious Diseases. 164:195-198,1991.

>>A different documentary shows the application of known dragon saliva to a peice of raw meat (deer?), with an untreated piece of meat, side by side with time lapse photos showing the treated piece putrify at an alarming rate, compared to the untreated meat. It looked like acid ate it away, while the other piece hardly changed. Could venom do that?

I'd be quite curious to see that piece of footage as well as any off-camera aspects.

>>Have there been any studies on carcasses taken from dragons, to see if there were traces of venom in the bloodstream?

No.

>>How is the venom delivered? Could it be carried by the saliva?
>>

It is delivered by duct leading up from different compartments of the venom gland. We have a paper under review currently that details the anatomy of the glands plus the venom composition and effects. We have shown shock-inducing, hypotensive and anticoagulant components to be the major toxins present. What needs to be kept in mind, stressed in fact as this is the key point to understand, is that this venom is an aid to the teeth. It is a combined arsenal as opposed to venom-only as in snakes. The deep wounds lead to blood loss and shock, so components that potentiate blood loss and shock would facilitate the incapacitation of the prey item. Once it is unconscious, the komodo can dis-embowel at its leisure.

Cheers
B
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Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

Hi,

thank you for answering my questions (not to mention, the brain workout!)

I'd be quite curious to see that piece of footage as well as any off-camera aspects.

It recently aired on Animal Planet, I'm sure many people saw it, but it was one of those " Animals that kill for a living" type of shows. Maybe they doctored it to make it more watchable?
I didn't record it.

It is delivered by duct leading up from different compartments of the venom gland. We have a paper under review currently that details the anatomy of the glands plus the venom composition and effects. We have shown shock-inducing, hypotensive and anticoagulant components to be the major toxins present. What needs to be kept in mind, stressed in fact as this is the key point to understand, is that this venom is an aid to the teeth. It is a combined arsenal as opposed to venom-only as in snakes. The deep wounds lead to blood loss and shock, so components that potentiate blood loss and shock would facilitate the incapacitation of the prey item. Once it is unconscious, the komodo can dis-embowel at its leisure.

Thank you for sharing this information. Very informative and easy to understand. Great stuff!

Susan.

I don't want to start a war with you, and I fully apologize for blasting you a while back on the venomous forum. However, please explain this. Why do you want to generalize/confuse the scientific terminology by labeling them all venomous like you did with the Duvernoy's glands. This terminology should note the differences and not confuse them. They ARE very different systems with different functions. A truly venomous snake has a complex delivery system and specific behaviors that accompany them for rapidly killing prey. The toxicological properties alone do not constitute a venom as previously defined. Why revive an old view with such a generalization?

Best Regards,
Jason
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"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

It comes to recognising rather than obscuring the evolutionary history. Artificial distinctions do not facilitate this. For example, with 'duvernoys' glands these were not a natural group and had nothing in common with each other other than the more general homology that also includes the atractapidid/elapidid/viperid type glands. Yes there are certainly differences in venom gland structures but it is variations on a theme. The glands and some of the toxins themselves have shared evolutionary history. 'rapid prey death' is an arbitrary term that contributes nothing to our understanding. They are derivations of the same gland and mutations of the some of the same toxins. I cannot see any logical reason to call a gila venomous but not a varanid when the venom composition is much more similar than between different kinds of elapids and the glands are more similar than between an elapid and a viperid.

It is much the same way that anything that was not obviously an elapid or viperid was put into the taxonomical dumping ground family 'Colubridae'. When in fact some were much closer to cobra than to corn snakes and the Colubridae family was not a natural group. Reassessment of historical assumptions using modern techniques.

Being venomous from an evolutionary perspective is not the same thing as being venomous from a practical (e.g. medical-legislative) perspective and this is something we have gone to great pains to try and make clear. It is much the same way that while all spiders are venomous, only rarities like Australia funnelwebs or Brazilian wandering spiders are of significant medical concern. But that does not change the fact that the other spiders are venomous. It is much the same thing in reptiles, we are trying to bring recognition to the glorious diversity that exists. Also by properly catagorising as venomous, this allows for a lucid roadmap in the use of these unique natural pharmacological libraries for drug design and development. We in fact all ready have a couple very promising lead compounds from varanid venoms.

Cheers
Bryan

>>I don't want to start a war with you, and I fully apologize for blasting you a while back on the venomous forum. However, please explain this. Why do you want to generalize/confuse the scientific terminology by labeling them all venomous like you did with the Duvernoy's glands. This terminology should note the differences and not confuse them. They ARE very different systems with different functions. A truly venomous snake has a complex delivery system and specific behaviors that accompany them for rapidly killing prey. The toxicological properties alone do not constitute a venom as previously defined. Why revive an old view with such a generalization?
>>
>>Best Regards,
>>Jason
>>-----
>>"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

The evolutionary history of oral secretions is there and true, but you have failed to include the history of behavior and morphology. These important histories are what the "arbitrary" groupings were based upon and while I agree they are not perfect, you are ready to throw them out the door? Did you jump the gun? I fully agree that new technology is available and is of use to reclassify our understanding of their evolutionary history. However we cannot allow a handful of proteins to guide this.
I am a molecular guy and I love genetics, it's what I do. But the popular trend today is to claim this as the Holy Grail and abandon the behavioral and morphological evolution that is paramount. It is NOT all in the nucleotide/amino acid sequences, and this is becoming more and more recognized.
We are finding that environment is having HUGE effects on gene expression (morphology and behavior).
Your comparison to spiders is NOT parallel as they all have the appropriate machinery to deliver venom effectively.
Duvernoy's gland is an appropriate term to classify the distinction that you say your trying so hard to emphasize. It is very obvious that venom is modified saliva and the Duvernoy's secretion has a homological history. What about the analogy?
Why not focus your research on the real function of the different secretions instead of claiming that since they are very similar that they must have the same function? Venom implies a function! How would this affect your ability for drug development? Why are you leaving form and function out of your evolutionary analysis? Your going backwards with this and similarising them not diversifying them with a blanket term, and then going through all the trouble to backpedal and say, “well that not what we really mean!" Please elaborate.
The evolutionary history of oral secretions is there and true, but you have failed to include the history of behavior and morphology. These important histories are what the "arbitrary" groupings were based upon and while I agree they are not perfect, you are ready to throw them out the door? I fully agree that new technology is available and is of use to reclassify our understanding of their evolutionary history. However we cannot allow a handful of proteins to guide this.
I am a molecular guy and I love genetics, it's what I do. But the popular trend today is to claim this as the Holy Grail and abandon the behavioral and morphological evolution that is paramount. It is NOT all in the nucleotide/amino acid sequences, and this is becoming more and more recognized.
We are finding that environment is having HUGE effects on gene expression (morphology and behavior).
Your comparison to spiders is NOT parallel as they all have the appropriate machinery to deliver venom effectively.
Duvernoy's gland is an appropriate term to classify the distinction that you say your trying so hard to emphasize. It is very obvious that venom is modified saliva and the Duvernoy's secretion has a homological history. What about the analogy?
Why not focus your research on the real function of the different secretions instead of claiming that since they are very similar that they must have the same function? Venom implies a function! How would this affect your ability for drug development? Why are you leaving form and function out of your evolutionary analysis? Your going backwards with this and similarising them not diversifying them with a blanket term, and then going through all the trouble to backpedal and say, “well that not what we really mean!" Please elaborate.
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"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

>>The evolutionary history of oral secretions is there and true, but you have failed to include the history of behavior and morphology. These important histories are what the "arbitrary" groupings were based upon and while I agree they are not perfect, you are ready to throw them out the door? Did you jump the gun?

Physically they share an evolutionary history and are the same glands. In regards to the duvernoys gland, morphologically they have as little to do with each other than they do with the atractaspidid/elapid/viperid glands. I am not saying that the front-fanged glands with their high-pressure systems are not unique innovations, they are, but this is not what makes them venomous. The venom is.

>>Your comparison to spiders is NOT parallel as they all have the appropriate machinery to deliver venom effectively.

Define effectively? That is about as arbitrary of a term as there is. A snake delivers it as effectively for the niche that it occupies. Relative efficiency of delivery does not define venomous. Effeciency is a lable we put on something. If it gets the job done, that is efficient enough for the animal involved.

> It is very obvious that venom is modified saliva

Actually it is as far from saliva as you can get. The proteins are not modified salivary proteins but rather mutated proteins normally expressed in other parts of the body. Three finger toxins for example are modified brain neuropeptides. Factor V or Factox X toxins are mutated versions of normal blood enzymes (FV and FX respectivey) that are now 1000 times more active and much more resistant to breakdown by normal body proteins.

>>Why not focus your research on the real function of the different secretions instead of claiming that since they are very similar that they must have the same function?

Neurotoxins, for example, have only one function, disabling of prey item. They are useless as lubricants.

> Venom implies a function!
>Why are you leaving form and function out of your evolutionary analysis?

We are indeed studying the relative bioactivities of the proteins and have found them to be just as potent as the ones found in what you insist are 'true venoms'.

We have shown that due to the extreme bioenergetic cost of producing venom that there is a strong selection process AGAINST it. Thus animals that don't use it, loose it very quickly. Such as the egg eaters, which includes not only a colubrid lineage (African egg eating snake) but two lineages of elapids (marbled sea snakes and certain species of the Australian terrestrial Brachyurophis genus) and also animals such as the ratsnakes which have secondarily evolved a new form of prey capture (powerful contriction) and have negligable venom glands, in contrast to say the Coluber genus which have maintained the glands.

Cheers
B
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

>Neurotoxins, for example, have only one function, disabling of prey item. They are useless as lubricants.

Only one function? Why do frogs and mushrooms have neurotoxins?

> Actually it is as far from saliva as you can get. The proteins are not modified salivary proteins but rather mutated proteins normally expressed in other parts of the body. Three finger toxins for example are modified brain neuropeptides. Factor V or Factox X toxins are mutated versions of normal blood enzymes (FV and FX respectivey) that are now 1000 times more active and much more resistant to breakdown by normal body proteins.

Correct. This is exaptation as decscribed by Steven J. Gould or preadaptation by Bock, which you have failed to acknowledge. Phospholipase A2 is found in rabbits. Are they venomous?

>We have shown that due to the extreme bioenergetic cost of producing venom that there is a strong selection process AGAINST it. Thus animals that don't use it, loose it very quickly. Such as the egg eaters, which includes not only a colubrid lineage (African egg eating snake) but two lineages of elapids (marbled sea snakes and certain species of the Australian terrestrial Brachyurophis genus) and also animals such as the ratsnakes which have secondarily evolved a new form of prey capture (powerful contriction) and have negligable venom glands, in contrast to say the Coluber genus which have maintained the glands.

Where is your proof of this? I believe Bruce A. Young has shown otherwise. That is that venom is NOT energetically expensive.

Cheers,
Jason
-----
"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

>>Only one function? Why do frogs and mushrooms have neurotoxins?

Those are different toxins in different organisms used for different purposes so that is a bit of a red herring. The snake toxins are not defensive weapons the way the organic toxins in frog skin secretions or in mushrooms are.

>>Phospholipase A2 is found in rabbits. Are they venomous?

That is another complete non-sequiter. Comparing to PLA2 in rabbit kneecaps is a very silly analogy. The mutated synovial form found in venoms however that have potent presynaptic neurotoxic effects however are venom components. The venom components are mutated normal body proteins, often retaining only the molecular scaffold. Thus the rabbit PLA2 are the similar to molecular ancestors of the venom components but are not venom components. That falls into the category of 'things any five year old could have told you'.

Fry, BG (2005) “From genome to ‘venome’: Molecular origin and evolution of the snake venom proteome inferred from phylogenetic analysis of toxin sequences and related body proteins.” Genome Research 15:403-420.
http://www.venomdoc.com/downloads/2005_BGF_Genome_2_Venome.pdf

>>
>>
>>Where is your proof of this?

Fry BG, Scheib H, van der Weerd L, Young B, McNaughtan J, Ramjan SFR, Vidal N, Poelmann RE, Norman JA (2007) Evolution of an arsenal: structural and functional diversification of the venom system in the advanced snakes (Caenophidia). Molecular & Cellular Proteomics 7(2):215-46
http://www.venomdoc.com/downloads/2008_BGF_Evolution_of_an_Arsenal.pdf

Li M, Fry BG, Kini RM (2005) “Putting the brakes on snake venom evolution: the unique molecular evolutionary patterns of Aipysurus eydouxii (Marbled sea snake) phospholipase A2 toxins.” Molecular Biology and Evolution 22(4):934-941.
http://www.venomdoc.com/downloads/2005_BGF_Aipysurus_eydouxii_PLA2.pdf

Li M, Fry BG, Kini RM (2005) “Eggs only diet: the shift in preferred prey by the Marbled sea snake (Aipysurus eydouxii) resulting in a loss of postsynaptic neurotoxicity.” Journal of Molecular Evolution 60(1):81-9.
http://www.venomdoc.com/downloads/2005_BGF_Aipysurus_eydouxii_3FTx.pdf

>I believe Bruce A. Young has shown otherwise. That is that venom is NOT energetically expensive.

It is simple biochemistry: each amino acid bond has an energetic cost of 4 ATP molecules. Thus milligrams of protein is a substantial investment of biological energy.

Ciao
B
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

No need to cite your papers Brian. I have read them. I only need one counterexample to counter and argument, which I have done. Other organisms are prime examples to combat this as they all have one origin. You know the vertebrate genome is 95% identical, what about the rest? That is where the differences lay.
Your right about phospholipase A2 and you proved my point quite clearly; the mere presence of such a compound does not show anything. The presence of those chemicals and their properties are just epiphenomena without ecological reference and fail to provide any useful data to the actual role they play in the organism.

You still have not answered my question: Why put a label on an animal that implies a danger that does not exist with old news? (see Zeller, E. A. 1948. Enzymes of snake venoms and
their biological significance. In F. F. Nord (ed.),
Advances in enzymology, Interscience Publ. N.Y.
8:4.59-49.5)

These animals are NOT venomous with any useful sense of the word.
Cheers,

Jason Dobry
-----
"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

>>Your right about phospholipase A2 and you proved my point quite clearly; the mere presence of such a compound does not show anything. The presence of those chemicals and their properties are just epiphenomena without ecological reference and fail to provide any useful data to the actual role they play in the organism.

Actually you seem to have fundamentally misunderstood my point. We are not talking about the simple presense of an ancestral form, we are talking about the accelerated molecular evolution of extensively duplicated and diversified molecular mutants that have newly conferred toxic activities.

>>
>>You still have not answered my question: Why put a label on an animal that implies a danger that does not exist with old news?

Relative danger is simply an evolutionarily irrelevant human perspective. And, as I have stated quite clearly many times, we have gone to great pains to make the point that venomous and dangerous are not synonymous.
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

>>>>fail to provide any useful data to the actual role they play in the organism.

If you've read the papers, you'll see that we are indeed starting to investigate exactly these links. Such as the highest presense of three finger toxins is in the gracile, fast moving non-front-fanged snakea that have only slightly or moderately enlarged rear maxillary teeth and predate upon fast moving, soft, thin skinned, non-dangerous prey items such as geckos and frogs. In contrast, the long fanged D. typus is an arboreal snake that includes birds as a major prey item, and the venom is rich in forms of the SVMP/ADAM toxins that are potently prothrombin-activating. Interestingly, these prothrombin activating forms are also the same as favored by Echis and Micropechis.

We are also investigating the impact of the diversification of venom in other lineages, such as the profound impact that a single toxin recruitment (factor V) had in the Oxyuranus/Pseudonaja clade.

SO we have not stopped at venom molecular evolution but are indeed trying to link together the entire spider web. But we are also not letting ourself be constrained by artificial or arbitrary terminology that obscures the evolutionary history.

Bye
B
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

Don't get mad please. As I think this is good stuff, and quite frankly I applaud your efforts. I just disagree with your conclusions. Fair enough?
Brian please understand, we really should be working together here.
Your talking about trying to gain a better understanding as to how these animals work correct? And then your claiming that I am talking about how this effects humans? I call BS. I would love to sit down with you and discuss this in person and perhaps we will one day have a chance; you will discover that I'm not attacking you. These things are hard to relay via internet.
That said, I do not believe a constricting snake should be compared to a rattlesnake when we are talking about oral secreting and their function. Its not the same thing. And to keep this on topic likewise with heloderma and varanus. So the makeup is the same they serve as different functions not just to he who is bitten (your self proclaimed motivation: drug development), but to the animal that uses it. How are they using it? A rattlesnake strikes and releases allowing the venom to take effect. It then tracks this prey and consumes it. A gardersnake does something very different and often eats its prey while still alive. Sir these are not the same systems.
When we talk about a venomous snake system there is all manner of other things involved other then a cocktail of toxins. And, the evolution involved with these other characteristics runs deep. Whether you want to believe it or not placing a blanket term over them all confuses things, not illuminates them. Additionally there was such terminology that served this purpose, But you want to eliminate it. This is what I fail to understand.
I really don't know what else to say.

Jason
-----
"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

>Additionally there was such terminology that served this purpose, But you want to eliminate it. This is what I fail to understand.

This seems to be the heart of the issue. We felt the terminology conveyed a similarity that simply was not there. Certainly the glands of atractaspidis/elapids/viperids are quite different than that found in other advanced snakes. However they are not quite as special as previously thought. Compressor muscles appear to be evolving in at least three other lineages. So the muscular connection is not what makes the gland a 'true venom gland'. The staggering diversity of the rest of the glands is far beyond what was conveyed by lumping them all together under the same term. Calling them all 'Duvernoys glands' misrepresented them as being similar to each other while obscuring their relationship with the 'true venom glands'.

As for predatory ecology, that also doesn't determine whether or not they are venomous. That is simply the variable of how they are using the venom. An area with as great of diversity as any other.

So at the end of the day, we are aiming for evolutionary clarity while emphasising the diversity to be found underneath this big tent. Using the same terms for homologous structures in this case is no different than using the same terms for Tiktaalik's "wrist" as for the human wrist, they are the same bones and therefore get the same name. In the case of the advanced snakes, it is the same gland so gets the same term. This is not to say that they all look identical, just as the homologous bones in Tiktaalik look quite different than those found in a human. That is the inherent beauty of evolution.

Cheers
B
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

So if this is the case why not diversify within the Duvernoy's gland? The only reason this argument has merit is because you changed the definition of what a venom is to fit these findings. A venom gland "was" homologue of the Duvernoy's gland. And it did/should have ecological significance. Which is I guess what your saying, but you just don't want to use "Duvernoy's gland. Instead you want to call them all venom glands, yet they are different. I still don't get why. The terminology should note the differences not confuse it! I would be right there with you otherwise.
-----
"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

Because there weren't any shared characteristics of the 'Duvernoy's gland'. That has been our key argument. The term is meaningless in light of the tremendous evolutionary tinkering combined with the non-monophyly of the 'colubrid' snakes. The different 'Duvernoy's glands' share nothing with each other. Its like the evolutionary history of the radius, despite the weird and wonderful forms its taken along the way, its still the same lump of tissue.
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

>I do not believe a constricting snake should be compared to a rattlesnake when we are talking about oral secreting and their function.

So does this mean that Pseudonaja are not venomous as they often use constriction to hold the prey in place while working in their very small fangs to deliver their quite small venom yields? This is in contrat to the rapid snap-bite-release (repeat) of Psammophis who then sit back and watch the small rat quickly turn purple die? The kill times of large Psammophis rival that of most 'true' venomous snakes. Or Thrasops who, despite not having enlarged rear teeth, cause the same horrifically fast and bloody death as boomslangs? I certainly hope you aren't saying boomslangs aren't venomous! Or, as another example, the truly massive fangs of Macropisthodon which are, proportional to head size, on par with the typical viper and bigger than many.

These are just a small sample of potential examples show-casing the staggering diversity, none of which is similar enough to be lumped under the same umbrella. Atractaspidids/elapids/viperids are not a natural group which was thought to be the case when the term 'Duvernoys gland' was coined to apply to the (then thought of as monophyletic and transitional) 'Colubridae'. In light of all the changes of our understanding of the evolutionary history of the snakes themselves and the much longer, and more complex, history of the venom glands the previous associated terminology is no longer any more appropriate than the taxonomical arrangements.

The same thing holds true for the mandibular venom glands of the Anguimorph lizards (to bring this thread back on topic). It is the same gland with the same chemical composition, yet more variation on a theme. Indeed, in the results we have now we have shown that the glands of the varanids is as complex and derived as that of the helodermatids and that the venoms are similarly complex and have diversified considerably.

The two sets of glands (maxillary and mandibular) share a common ancestry, being derivations of a previous system found on both jaws in the common ancestor. The ancetral toxin types remain amongst the most medically important today.

Cheers
B
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

>The same thing holds true for the mandibular venom glands of the Anguimorph lizards (to bring this thread back on topic). It is the same gland with the same chemical composition, yet more variation on a theme. Indeed, in the results we have now we have shown that the glands of the varanids is as complex and derived as that of the helodermatids and that the venoms are similarly complex and have diversified considerably.

>The two sets of glands (maxillary and mandibular) share a common ancestry, being derivations of a previous system found on both jaws in the common ancestor. The ancetral toxin types remain amongst the most medically important today.

This thread has turned out to be most informative, though you 'scientists' lost me at some points, thanks to the information given , I have a better understanding of venom in varanids. Thank you!

Susan.

Here the download link for our first paper on varanid venom. More to come in due time.

http://www.venomdoc.com/downloads/2006_BGF_Nature_squamate_venom_press.pdf

Cheers
B
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

I don't have any experience working with those animals, so I cannot give a knowledgeable response to this post.
I do agree that Colubridae is a generic group and this all does need work. However I think that your venomous grouping of all these animals is more of the same thing you are just using a different tool. That doesn't make it any better. It will require sequencing of entire genomes to sort this thing out not just a few hundred proteins.
-----
"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

>> However I think that your venomous grouping of all these animals is more of the same thing you are just using a different tool.

The crucial difference is that we are using homologous terminology to refer to a natural group. That is the key to all of this.

Cheers
B
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

To what the massive group of squamata?
-----
"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

>>I don't have any experience working with those animals, so I cannot give a knowledgeable response to this post.

Here is an image showing the bones
http://scienceblogs.com/pharyngula/2008/07/14/fins_patterns.gif

and a link to a good article about it by Carl Zimmer
http://carlzimmer.com/articles/index.php?subaction=showfull&id=1201035230&archive=&start_from=&ucat=11&

Homologous parts = homologous names.

Cheers
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

Homologous parts = homologous names

But Bro, when homology diversifies the differences need to be acknowledged. This is my knee-jerk comment. I will read the link now.
Cheers
-----
"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

>>Homologous parts = homologous names
>>
>>But Bro, when homology diversifies the differences need to be acknowledged. This is my knee-jerk comment. I will read the link now.

Of course! But without obscuring the evolutionary history. I am not saying there hasn't been diversification, of course there has, but this needs to be recognised without making artifical designations.

That is the devil in the detail.
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com

That is a great article, and I fully agree. I have to admit my ignorance of this recent discovery as my focus has been entirely on genetics recently, but I do love anatomy. I was even a TA for comparative anatomy while a student, but I realized the importance of genetics too. I am in complete agreement with integrated biology. This is what I was trying to say in an earlier post about the need for both.
Anyway Brian, this discussion has been great, but I REALLY have some work get done. I still stand by my argument, I think you have made some VERY valid points that I plan on looking into more deeply. I do hope to continue this conversation, and I thank you for answering my questions.
Cheers,
Jason
-----
"Relax, Don't Worry, Have a Homebrew!" Charlie Papazian

I cannot see any logical reason to call a gila venomous but not a varanid when the venom composition is much more similar than between different kinds of elapids and the glands are more similar than between an elapid and a viperid.

Being venomous from an evolutionary perspective is not the same thing as being venomous from a practical (e.g. medical-legislative) perspective

So, are Gilas 'practically venomous' versus varanids being venomous 'from and evolutionary perspective'?

Is the difference between Gila and Varanid venom's effectiveness, more to do with concentration or composition?

Thanks,
Susan.

>>So, are Gilas 'practically venomous' versus varanids being venomous 'from and evolutionary perspective'?
>>
>>Is the difference between Gila and Varanid venom's effectiveness, more to do with concentration or composition?
>>
>>

Quantity and relative efficiency of delivery is what makes them human medically important. The bioactivities are very much the same.

But we are evolutionarily irrelevant. Any effects on us are mereely pleasent side-effects. For the longest time simple human arrogance has filtered our view. Whether or not it caused notable effects on us was taken as an important piece of data. What is important is not the perspective of a 50 kilo human but rather that of say for example a 5 gram frog.

Cheers
Bryan
-----
Dr. Bryan Grieg Fry
~~~~~~~~~~~~~~~~~~~~~~
Venomics Research Laboratory,
Department of Biochemistry,
Bio21 Institute,
University of Melbourne
~~~~~~~~~~~~~~~~~~~~~~
http://www.venomdoc.com