By Alexandra Balcer
QUICK! What do black mambas, botulinum toxin, and Box Jellyfish have in common? Aside from all starting with the letter B, all three are harmful to humans. I’m sure if you asked the average American to rank the three from painful to downright deadly you’d get a list that looked something like this:
1) BLACK MAMBA
(Ahhhhh, run away!)
2) Botulinum Toxin
3) Box Jellyfish
(Dawww, how cute!)
Cuteness aside, the Box Jellyfish, or Chironex fleckeri, is actually the most venomous creatures to float about the earth. Normally only a hazard to fish and the wayward crustacean, the Box Jellyfish produces a venom that is extremely painful and potentially lethal to humans. How is it that such a small, translucent organism can pack such a powerful punch? It all comes down to their little stinging capsules, or nematocysts, pictured below.
Imagine these tiny harpoons piercing your skin...
(If you want to see how nematocysts work in real time, check out this really neat high speed video collected at the University of Hawaii).
These nematocysts are chalked full of venomous proteins, vaguely titled CfTX-A and CfTX-B, which upon contact with tissues induce cutaneous pain (skin pain), necrosis (cell death), inflammation (swelling), cardiovascular collapse (cessation of proper circulation), hypertension (high blood pressure) followed by hypotension (low blood pressure), and cardiac arrest (loss of heart function) .
So if you are unlucky enough to get tangled up with a Box Jellyfish, expect a major cardiac episode. This little cnidarian is able to end your life by disrupting some of your heart tissue’s most fundamental functions.
In order for your heart to beat regularly the muscle cells in the walls of your heart have to relax and contract to pump blood throughout your body. This movement of blood provides your tissues with the essential nutrients and oxygen they need to survive. These contractions are controlled by the influx and efflux of special small molecules, called ions, which act to dictate the vital cell mechanisms. The most important ions in this process are calcium (Ca+2), potassium (K+), and sodium (Na+) and they act in tandem to cause muscle contractions and perpetuate action potentials, or electrical signals, within the cell .
To put it simply: Ca+2 are in charge of the contraction machinery and Na+/K+ are in charge of electrical signaling.
An investigation lead by M.R. Mustafa of the University of Malay in Malaysia helped shed light on how Box Jellyfish venom disturbs these cellular mechanisms that could lead to cardiovascular collapse and cardiac arrest. Based on his research, it appears that the venomous proteins cause an influx of calcium into the cell which causes general cell overload. This particular overload is measured by how well a cell can contract and create/maintain those electrical signals .
Another very interesting study conducted by Diane L. Brinkman at the University of Auckland in Australia illustrated how blood pressure varies with exposure to Box Jellyfish venomous proteins CfTX-A and CfTX-B, as well as a relative toxin CfTX 1 and CfTX-2 known to other members of the Jellyfish family. In both cases, after application of the respective venom, they observed a rapid increase in blood pressure followed by a prolonged decrease in blood pressure indicating that the heart could no longer sustain contractions to keep the blood flowing to maintain the blood pressure. This loss of circulatory activity is experimental evidence for cardiac collapse .
Cardiac collapse… Cardiac arrest… Death…Now just because this jelly could kill you, it doesn’t mean that you should avoid the ocean forever. Being only about 10 inches across and 10 feet long, you should totally be able to see them before you get caught by their stinging capsules. Wait, they are clear or white in color... That’s not too hard to see in clear or white water, right? Uhhh. Stay safe kids. And just remember, if you get stung by a Box Jellyfish don’t urinate on the affected area, because who wants to smell like pee when they’re dead?
 Brinkman. D.L., N. Konstantakopoulos, B.V. McInerney, J. Mulrenna, J.E. Seymour, G.K. Isbister, and W.C. Hodgson. 2014. Chironex fleckeri (Box Jellyfish) Venom Proteins: Expansion of a Cnidarian Toxin Family that Elicits Variable Cytolytic and Cardiovascular Effects. The Journal of Biological Chemistry. M113.534149.
 Mustafa, M.R., E. White, K. Hongo, I. Othman, and C.H. Orchard. 1995. The Mechanisms Underlying the Cardiotoxic Effects of Toxin from the Jellyfish Chironex fleckeri. Toxicology and Applied Pharmocology 133:196-206.
Pictures and Video:
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