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Hiroshi Nagai
Hiroshi Nagai

Longer Jellyfish Stingers Inflict More Pain, Study Says 

Hiroshi Nagai
Hiroshi Nagai

Not all jellyfish inflict a painful sting. Coming in contact with certain types of jellies, like the moon jelly, is relatively painless, even though some harmless jellyfish are still venomous. By contrast, a sting from the box jellyfish Chironex fleckeri is severely painful and can be fatal

But why? In a new study in PLOS ONE, researchers from Tokyo University of Marine Science and Technology say they have found that the longer the jellyfish’s stinging organ, the more painful its sting. They propose that the deeper in the body the jellyfish stinger penetrates, the more severe the pain it causes. 

Jellyfish immobilize their prey and defend themselves against attackers using nematocysts, needle-like stingers usually located within the tentacles. When jellyfish make contact with another species (like a fish or a human swimmer), these nematocysts fire, injecting venom-carrying tubules into the unlucky recipient. (Watch the process close-up in this video.)

In the study, the researchers compared the length of discharged nematocyst tubules from different types of jellyfish found off the coast of Japan, both species whose stings cause severe pain and those that are relatively harmless. Dangerous species like Chironex yamaguchii (a box jellyfish that has caused several deaths) had significantly longer nematocyst tubules than harmless species like the moon jelly. Moderately painful stinging jellyfish like Chrysaora Pacifica had tubule lengths between 100 micrometers and 200 micrometers, compared to the deadly species, which had venom injectors more than 200 micrometers (one species, Carybdea brevipedalia, shot tubules longer than 600 micrometers).

X, Y, and Z correspond to nematocyst tubules from not-painful, moderately painful, and severely painful jellyfish stings, respectively. The two boxes (“a” and “b”) correspond to the distribution of nerves under the skin. Image Credit: Kitatani et al., PLOS ONE (2015)


The authors hypothesize that because these longer stingers penetrate deeper below the skin, where there are more nerve endings, people feel more pain from these stings. The more harmless species of jellyfish still inject venom, but since they don't go as deeply into the skin, it’s harder to feel. More painful jellyfish stings may come from the physical stimulation of the pain receptors below the skin. In addition, “the subsequent persistent pain in the region of the sting might be generated due to the destruction of tissue by the deeply injected venom,” they write. 

This study only examined a handful of jellyfish species in Japan, so it’s possible that a larger sample of international species might confound these results. And this study doesn’t examine the differences in venom between the species, which also might create a more painful affect (some snake venom, for instance, contains a combination of toxins that attacks pain-sensing nerves). However, it might be a good idea to stay away from jellyfish with super-long venomous needles stored in their tentacles regardless. 

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Andreas Trepte via Wikimedia Commons // CC BY-SA 2.5
Climate Change Has Forced Mussels to Toughen Up
Andreas Trepte via Wikimedia Commons // CC BY-SA 2.5
Andreas Trepte via Wikimedia Commons // CC BY-SA 2.5

Researchers writing in the journal Science Advances say blue mussels are rapidly evolving stronger shells to protect themselves against rising acid levels in sea water.

Bivalves like mussels, clams, and oysters aren’t good swimmers, and they don’t have teeth. Their hard shells are often the only things standing between themselves and a sea of dangers.

But even those shells have been threatened lately, as pollution and climate change push the ocean's carbon dioxide to dangerous levels. Too much carbon dioxide interferes with a bivalve’s ability to calcify (or harden) its shell, leaving it completely vulnerable.

A team of German scientists wondered what, if anything, the bivalves were doing to cope. They studied two populations of blue mussels (Mytilus edulis): one in the Baltic Sea, and another in the brackish waters of the North Sea.

The researchers collected water samples and monitored the mussel colonies for three years. They analyzed the chemical content of the water and the mussels’ life cycles—tracking their growth, survival, and death.

The red line across this mussel larva shows the limits of its shell growth. Image credit: Thomsen et al. Sci. Adv. 2017

Analysis of all that data showed that the two groups were living very different lives. The Baltic was rapidly acidifying—but rather than rolling over and dying, Baltic mussels were armoring up. Over several generations, their shells grew harder.

Their cousins living in the relatively stable waters of the North Sea enjoyed a cushier existence. Their shells stayed pretty much the same. That may be the case for now, the researchers say, but it definitely leaves them vulnerable to higher carbon dioxide levels in the future.

Inspiring as the Baltic mussels’ defiance might be, the researchers note that it’s not a short-term solution. Tougher shells didn’t increase the mussels’ survival rate in acidified waters—at least, not yet.

"Future experiments need to be performed over multiple generations," the authors write, "to obtain a detailed understanding of the rate of adaptation and the underlying mechanisms to predict whether adaptation will enable marine organisms to overcome the constraints of ocean acidification."

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University of Adelaide
Scientists Find Potential Diabetes Drug in Platypus Venom
University of Adelaide
University of Adelaide

The future of diabetes medicine may be duck-billed and web-footed. Australian researchers have found a compound in platypus venom (yes, venom) that balances blood sugar. The team published their results in the journal Scientific Reports.

So, about that venom. The platypus (Ornithorhynchus anatinus) may look placid and, frankly, kind of goofy, but come mating season, the weaponry comes out. Male platypuses competing for female attention wrestle their opponents to the ground and kick-stab them with the venom-tipped, talon-like spurs on their back legs. It’s not a pretty sight. But it is an interesting one, especially to researchers.

Animal venoms are incredible compounds with remarkable properties—and many of them make excellent medicine. Many people with diabetes are already familiar with one of them; the drug exenatide was originally found in the spit of the venomous gila monster. Exenatide works by mimicking the behavior of an insulin-producing natural compound called Glucagon-like peptide 1 (GLP-1). The fact that the lizard has both venom and insulin-making genes is not a coincidence; many animal venoms, including the gila monster’s, induce low blood sugar in their prey in order to immobilize them.

It’s a good strategy with one flaw: GLP-1 and compounds like it break down and stop working very quickly, and people who have trouble making insulin really need their drug to keep working.

With this issue in mind, Australian researchers turned their attention to our duck-billed friends. They knew that platypuses, like people, made GLP-1 in their guts, and that platypuses, like gila monsters, make venom. The real question was how these two compounds interacted within a platypus’s body.

The researchers used chemical and genetic analysis to identify the chemical compounds in the guts and spurs of platypuses and in the guts of their cousins, the echidnas.

They found something entirely new: a tougher, more resilient GLP-1, one that breaks down differently—and more slowly—than the compounds in gila monster spit. The authors say this uber-compound is the result of a "tug of war" between GLP-1’s two uses in the gut and in venom.

"This is an amazing example of how millions of years of evolution can shape molecules and optimise their function," co-lead author Frank Gutzner of the University of Adelaide said in a statement.

"These findings have the potential to inform diabetes treatment, one of our greatest health challenges, although exactly how we can convert this finding into a treatment will need to be the subject of future research."

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