Venom components and metals in scorpions

[2nscorpx]

I have heard that scorpions' bodies have metals in them, specifically in the aculeus and the ends of the chelae...also, I have "heard" that the venom of a scorpion is unique, and there are several components to them. Are these true, and does anyone know of any sources of these, either here or elsewhere? I have looked, yes, but I have not found credible sources. Anyone care to devote a little time to explain? Thanks!

Edit: To give a background here, some questions may be: "a scorpion's venom acts exceptionally quickly...why?" or "what are the toxins in the venom, such as beta toxins, gamma toxins"...how are these venoms medically significant, not only negatively, but positively, etc...I know the venom of R. junceus and L. quinquestriatus have been used for treatment of cancers, but are there other specific and credible papers on this? I apologize if the question seems rushed...

 

[ShredderEmp]

The scorpions venom is full of protein compounds that usually destroy the nervous system, but there is one scorpion (Hemiscorpius lepturus) has a cytotoxic venom.

The venom potency on predators/prey has one important variable, size. The smaller the animal, the quicker the reaction. This is why some stings cause deaths hours after.

Many animals other than scorpions have neurotoxic venoms/poisons, so it's not unique to just scorpions.

I have also heard that metal rumor, whereas it doesn't surprise me because it makes sense, I just don't know if it's true.

 

[2nscorpx]

Hemiscorpius lepturus....the species that should be kept in a biohazard compound. The venom effects are certainly not very nice. Thanks for the help! Anyone else like to add on?

 

[VictorHernandez]

I have been asking myself about the metals thing as well for quite a while. I'm not sure if they create them on their own, from food items, or they get it from the soils. I wonder if were supposed to sprinkle iron dust or something in there substrate, or food.

 

[ShredderEmp]

Hemiscorpius lepturus....the species that should be kept in a biohazard compound. The venom effects are certainly not very nice. Thanks for the help! Anyone else like to add on?

Haha, I would agree. I know I wouldn't keep one with the chance of renal failure, haemolysis, necrotic ulcers, ankylosis, and not to mention psychological problems and death.

After reading Victor's comment that made me think that if they do have metals, that it would most likely come from food. As in humans, lettuce apparently has iron that we need.

 

[vespers]

Regarding metals: Its briefly discussed starting at 6:37 on this portion of a BBC program:

http://www.youtube.com/watch?v=d4NRw_WHcvw

 

[veliravia]

My apologies, I would have replied sooner but had to wait for account authorization (been lurking for a while, but only yesterday felt compelled to actually join).

I have heard that scorpions' bodies have metals in them, specifically in the aculeus and the ends of the chelae

Correct, and the authors of one paper[SUP][1][/SUP] found that zinc, manganese, calcium, and chloride began to accumulate in different parts of a scorpion Vaejovis spinigeris after ecdysis, namely the “pedipalp teeth, tarsal claws, cheliceral teeth and sting (aculeus)” – the “tools” of the scorpion. They found similar results in ants and believe this indicates that metal incorporation into “tools” happened in some common ancestor, before divergence.

I have "heard" that the venom of a scorpion is unique, and there are several components to them

Also true. Scorpions, like most other venomous arthropods, have a collection of components in their venoms. These include not only toxins, but also enzymes, small peptides, salts, and small bioactive molecules. Another paper[SUP][2][/SUP] that examined the toxic components of Heterometrus petersii and found “[ten] known families of venom peptides and proteins…which include: two families of potassium channel toxins, four families of antimicrobial and cytolytic peptides, and one family from each of the calcium channel toxins, La1-like peptides, phospholipase A2,and the serine proteases.” Some of these will selectively target ion channels, others will directly kill cells, and still others will degrade proteins. Toxins can be very specific to a species, in that only scorpions of that species will produce this specific toxin. Of the toxins that act against ion channels, some affect a whole range of channels whereas others might be specific to a single isoform of a particular channel. These properties can be exploited for research applications, as insecticides, and even as drugs (google “Prialt”).

a scorpion's venom acts exceptionally quickly...why?

The speed at which a scorpion’s venom would act depends on several factors, including the site of envenomation, the amount of venom injected, the size of the target, as well as the composition of the venom. Arthropod venoms generally have a strong affinity for ion channels (consider they’ve had hundreds of millions of years of evolution to develop extremely effective toxins) and once having associated with their particular target are then able to exert their effects (causing nerves to fire or muscles to become paralyzed). Given a high affinity, you generally don’t need as much toxin to get an effect. The symptoms of scorpion stings likely vary due to different toxin compositions. Keep in mind also that the targets of these toxins, ion channels, are found not only in the nervous system, but also in muscle (including the heart) and even the pancreas (β-cells of the pancreas, responsible for insulin secretion, can be induced to secrete insulin by a tarantula toxin (guangxitoxin), even in Type II diabetes).

what are the toxins in the venom, such as beta toxins, gamma toxins

I mentioned earlier some of components of toxins, but there are classes into which certain toxins fall. For example, consider the toxins Lqq5[SUP][3][/SUP] and Css4[SUP][4][/SUP], from Leiurus quinquestriatus quinquestriatus and Centruroides suffusus suffusus, respectively. The former is an α-mammal scorpion toxin (from Old World scorpions); these toxins tend to inhibit the recovery of sodium channels from fast inactivation, preventing neurons from firing. The latter toxin, on the other hand, is a β-mammal scorpion toxin (from New World scorpions) and promotes activation of sodium channels, causing “spontaneous and repetitive firing” in neurons. Scorpion toxins will contain a variety of toxins that act on different channels in different ways, but some of these toxins may fall into a certain class that shares characteristics with other toxins, in the way by which they exert their effect (which may be conserved only within scorpions from a certain geographical region, for example).

how are these venoms medically significant, not only negatively, but positively

The positive medical significance of scorpion venoms is derived from their particular affinity to a certain type of channel, the same with other arthropods. Chlorotoxin[SUP][5][/SUP], from LQ, “[is] under phase II clinical trial by Sinai Medical Center and TransMolecular under the name TM-601. It crosses blood-brain and tissue barriers and binds to malignant brain tumor cells without affecting healthy tissue. Radioiodinated TM-601 is used to treat malignant glioma.”

I hope that adequately answered some of your questions. If you're interested in reading any of these papers, but don't have access, let me know and I can provide them.



[HR][/HR]
References:

[1] Schofield, R. M. S., et al. "Zinc is incorporated into cuticular “tools” after ecdysis: The time course of the zinc distribution in “tools” and whole bodies of an ant and a scorpion." Journal of insect physiology 49.1 (2003): 31-44.
[2] Ma, Yibao, et al. "Molecular diversity of toxic components from the scorpion Heterometrus petersii venom revealed by proteomic and transcriptome analysis." Proteomics 10.13 (2010): 2471-2485.
[3] http://www.uniprot.org/uniprot/P01481
[4] http://www.uniprot.org/uniprot/P60266
[5] http://www.uniprot.org/uniprot/P45639

 

[Michiel]

Consult the online version of the biology of scorpions..it is not a rumour, about a quarter of the aculeus consists of metals like zinc and such.
Venomology is not one of my interests,but I do know you can find tons of papers on the subject on the net. You could also register to the journal of venomous animals and toxins (including tropical diseases) for free....

Verstuurd van mijn GT-I9001 met Tapatalk

 

[2nscorpx]

Wow, thanks everyone! That is what I was looking for. Thanks for the thoroughness and the specific sources. I know on SKF (Skorpionforen.eu) they have a very informative section on venom, but I still couldn't find things like the specific reason why, e.g. the venom can be beneficial, not just the fact that it is. Thanks all.

 

[Avery]

Great first post, veliravia! In this thread I can only offer my appreciation for such an interesting read. Thanks.