Study of ray toxin potency

[Tongue33]

If anyone has a link to this paper, I'd be greatful, I can't seem to find it electronically....

Man I read all about that and I believe i read the link and whole paper that is connected.. But I forgot the link I was studying up during a debate on rays and Hand feeding..

If i remember it i'll let you know Keep looking I know the rest of it is on the net!!!

 

[davo]

Don't worry, the_deeb pointed me in the right direction. If anyone can't view the paper that wants too, pm me, I'll send you the pdf file... think you need to be able to sign in to read it, some you do some you dont.

 

[ewurm]

Found this great paper on why the freshwater stingray venom. I had read that the venom from the freshwater rays was more potent, but had never really seen any evidence of it. I found this paper, posted online as a word document if anyone would like a copy.

Study reveals stingray potency


Pictures by Neil Hepworth

Brazilian scientists have undertaken a study which shows why freshwater stingrays are so much more venomous than their marine counterparts.

While marine stingrays have small numbers of carefully placed venom-secreting cells, freshwater rays have venom producing cells covering the entire stinger, which makes the wounds they inflict much more painful.

Scientists working in the Laboratory of Cellular Biology at Sao Paulo's Instituto Butantan compared the morphology of the "stingers" of a number of Brazilian rays spanning marine and freshwater species and found some striking differences in the structure of their stingers.

Their findings are due to be published shortly in the journal Toxicon.


Stingers
Most species have between one and three stingers on the end of their tails, which are covered with special epidermal protein cells that secrete a toxic venom.

In marine species, the protein cells are located only around or inside special ventrolateral grooves which run along the sides of the stinger.

However, in freshwater stingrays, there are much greater numbers of protein secretory cells and they're spread over the entire surface of the epidermis, so even a small nick in the skin of the victim could see venom being introduced and a deep wound could see a high dose delivered.

Although stingrays are made up of soft, pliable cartilage, their stingers are mineralised, hard and serrated, which allows them to puncture and tear skin easily.




Reflex
When stingrays are touched dorsally they can often use a reflex action to rapidly whip the tail upwards which can cause the victim to be pierced by the stinger.

Since rays tend to live buried beneath a layer of sand, they can be inadvertently stepped upon by people bathing or wading in areas where they occur.

The resulting wounds cause intense local pain, swelling, redness and secondary infection by bacteria.

Wounds from the freshwater stingrays are considered the worst of all and are often accompanied by tissue necrosis, which causes the flesh around the wound to be eaten away.

A number of freshwater stingray species are kept in aquaria.

For more information see the paper: Pedroso CM, Jared C, Charvet-Almeida P, Almeida MP, Neto DG, Lira MS, Haddad V, Barbaro KC, Antoniazzi MM (2007) - Toxicon. 2007 Jun 23.


I highlighted the pertinent portion in red for those averse to reading

I followed up with a search for the Toxicon paper, this is all that I found:

http://www.medscape.com/medline/abstract/17669455

It's a study of the venom of P. Falkneri and the marine species D. Guttata and shows scientifically the difference between the venom of the two species. Toxicologists, Toxinologists and pharmacologists would be able to translate the specific action of the protein venom to layman terms, but I don't think we have any on the board unfortunately. I'll again highlight in red the pertinent portions.

Barbaro KC; Lira MS; Malta MB; Soares SL; Garrone Neto D; Cardoso JL; Santoro ML; Haddad Junior V
Laboratory of Immunopathology, Butantan Institute, Av. Vital Brazil 1500, 05503-900 São Paulo, SP, Brazil. kbarbaro@butantan.gov.br
Stingrays are elasmobranchs found along the seacoast and in some rivers of Brazil. Pain is the most conspicuous symptom observed in patients wounded by the bilaterally retroserrate stingers located in the tail, which are covered by glandular and integument tissues. In addition, cutaneous necrosis is commonly observed in injuries caused by freshwater stingrays. The aim of this work was to characterize and compare certain properties of tissue extracts obtained from the glandular tissues covering the stinger apparatus of Potamotrygon falkneri and Dasyatis guttata stingrays. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), tissue extracts have similar bands above 80 kDa, but most differences were observed below this molecular mass. Lethal, dermonecrotic and myotoxic activities were detected only in P. falkneri tissue extract. Edematogenic activity was similar and dose dependent in both tissue extracts. Nociceptive activity was verified in both tissue extracts, but P. falkneri presented a two-fold higher activity than D. guttata tissue extract. No direct hemolysis, phospholipase A2 and coagulant activities were observed in both tissue extracts. Antigenic cross-reactivity was noticed by ELISA and Western blotting, using antisera raised in rabbits. Species-specific sera reacted with several components of both tissue extracts, noticeably above 22kDa. Both tissue extracts presented gelatinolytic, caseinolytic and fibrinogenolytic activities, which were not caused by the action of metalloproteinases. Hyaluronidase activity was detected only in P. falkneri tissue extract. Our experimental observations suggest that P. falkneri tissue extract is more toxic than D. guttata tissue extract. These results may explain why injuries caused by freshwater stingrays are more severe in human accidents.

 

[FSM]

tissue necrosis...something I would love to avoid.

 

[Gr8KarmaSF]

Nice info wurm. I am going to copy this post and add it to the ray safety thread!!!!

 

[Zoodiver]

Nice find Wurm! That study is far more in depth than why I tell people they are different. Usually I just say:

"I've been tagged by both: Marine rays make you hurt, FW rays make you wish for death."

 

[ewurm]

Nice find Wurm! That study is far more in depth than why I tell people they are different. Usually I just say:

"I've been tagged by both: Marine rays make you hurt, FW rays make you wish for death."

Sounds like you are a victim of the increased amount of secretory cells. I'd like to experience an envenomation just to know what it's like. If it happens, I'll be saying that I wish it wouldn't have happened.

 

[Miles]

Awesome article Davo, very interesting subject.

I agree!

I wonder why freshwater stingrays are so potent?

 

[ewurm]

I agree!

I wonder why freshwater stingrays are so potent?

Thanks Miles! I'll merge my thread with this one. You sure are digging deep to ensure topics aren't double posted! We appreciate the effort.

 

[rayman]

And another one:

Biological and biochemical properties of the Brazilian Potamotrygon stingrays: Potamotrygon cf. scobina and Potamotrygon gr. orbignyi

Abstract

Stingrays of the family Potamotrygonidae are widespread throughout river systems of South America that drain into the Atlantic Ocean. Some species are endemic to the most extreme freshwater environment of the Brazil and cause frequent accidents to humans. The envenomation causes immediate, local, and intense pain, soft tissue edema, and a variable extent of bleeding. The present study was carried out in order to describe the principal biological and some biochemical properties of the Brazilian Potamotrygon fish venoms (Potamotrygon cf. scobina and P. gr. orbignyi). Both stingray venoms induced significant edematogenic and nociceptive responses in mice. Edematogenic and nociceptive responses were reduced when the venom was incubated at 37 or 56 °C. The results showed striking augments of leukocytes rolling and adherent cells to the endothelium of cremaster mice induced by both venoms. The data also presented that injection of both venoms induced necrosis, low level of proteolytic activity, without inducing haemorrhage. But when the venoms of both stingray species were injected together with their mucus secretion, the necrotizing activity was more vigorous. The present study provided in vivo evidence of toxic effects for P. cf. scobina and P. gr. orbignyi venoms.

http://www.sciencedirect.com/scienc...serid=10&md5=f59cc311965ec541da847741ff4855f8