By Steve Allain, Imperial College London
One of my biggest pet peeves as a herpetologist is the trouble that some people have with distinguishing between a venom and a poison – I thought I’d address this early on as I don’t wish to confuse anyone. There is an easy way to remember which is which, a venom has to be injected and a poison has to be ingested. It is very likely that if you ingested a venom it wouldn’t have any effect on your body due to the same protective properties in the stomach that protect us from pathogens, such as the change in pH. This would denature the proteins in the venom and potentially make them harmless. You also have to remember that for venom to be effective, it has to reach your circulatory system and there is a low chance of this happening in the stomach.
When asked to name a venomous animal, a whole myriad of answers come to mind such as snakes, scorpions and bees. Let’s use the example of bee venom to highlight something truly remarkable about venoms. Due to the fact that they are a complex cocktail of proteins, peptides and salts, they have other properties other than causing pain and immobilising prey. Honey bee venom contains a peptide called melittin and in lab trials this has shown to have some truly remarkable properties. The first is that when using gold nanoparticles carrying melittin, researchers have found that the peptide is able to puncture holes in the hard and protective protein envelope of HIV, whilst causing no ill effects to healthy human cells. This could lead to a future cure for HIV by using a similar technique, but of course it will be a long while yet as more research is needed to ensure the procedure is both safe and effective in people.
If I asked you what you thought was the most expensive liquid on the planet you may suggest some plausible answers such as a bottle of Dom Pérignon Champagne or even Chanel No. 5. Both of these are unfortunately wrong. The correct and surprising answer is scorpion venom, which is a staggering $39 million a gallon. One of the reasons why the venom is so expensive is that the yield from each scorpion is very small, so you’d need to milk an impossible number to be able to collect that gallon. Current research is focusing around the potential for scorpion venom to one day be used as an alternative painkiller – one with no nasty opioid addictive side-effects. It is also hoped that in the future debilitation diseases such as lupus and rheumatoid arthritis will be cured with the power of scorpion venom so keep an eye on this space!
Despite venom having potentially lethal effects, it’s always amazing to consider that mechanisms of action can help treat certain medical conditions, something that is very far removed from the biological role of the original toxin. The venom of certain species of snakes is currently being trialled as a cure for diseases such as cancer and diabetes. Scientists now recognise that venom’s ability to do this is because the venom from snakes (and other reptiles) usually targets the same or very similar physiological pathways. For example
a component of venom found in the copperhead (Agkistrodon contortrix), has experimentally been shown to reduce the growth of breast cancer cells. This is just one of the many ways venoms can potentially help us in the future, including those listed above. By understanding how the venoms operate in these systems, drugs can then be specifically designed to target these diseases.
Venoms are a toxic cocktail that seem paradoxical as they have the power to kill but also the power to cure. This latter property is still in its development phase but with thousands of venomous species out there, it’s only a matter of time until drugs enter the market that are based on molecules once restricted to the venom glands of an exotic species. Most of the drugs in use to today originate from nature – mostly from plants. Perhaps by investigating the composite venoms of different animals, we’ll find a treasure trove of new drugs that are able to treat a whole manner of different illnesses and diseases. Who knows, we may even find a solution to the inevitable antibiotics apocalypse – but that is a story for a different time.
I’m a Master’s student at Imperial College London studying Ecology, Evolution and Conservation. My main research areas concern amphibian populations and their disease dynamics. I’ve been blogging for a few years now on a number of different platforms but if you’d like to know more about my research then please feel free to follow me on Twitter.