Toxic moments

First, a story came by on NPR in which a tale of five dead hunters in Oregon played a central role, as did the terrible poison tetrodotoxin. And then an episode of the tv series Death in Paradise in which this poison plays a central role. Rough-skinned newts, pufferfish, and garter snakes all have parts to play in the story, as do arms races in evolution. And of course tetrodotoxin and the entertainments of Death in Paradise.

Wikipedia on the poison:

Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an order that includes pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered in these fish and found in several other aquatic animals (e.g., in blue-ringed octopuses, rough-skinned newts, and moon snails), it is actually produced by certain infecting or symbiotic bacteria like Pseudoalteromonas, Pseudomonas, and Vibrio as well as other species found in the animals

On to the dead hunters, whose tale was entertainingly told by Carl Zimmer on his Discover Magazine blog, in “A Beautiful Web of Poison Extends A New Strand” of 6/21/11. Carl was just back from the annual meeting of the Society for the Study of Evolution, and offered this report:

My favorite [paper at the meeting] was a talk about the rough-skinned newt, the most ridiculously poisonous animal in America.

The scientific tale of the rough-skinned newt begins five decades ago, with a story about three dead hunters in Oregon. Reportedly, the bodies of the hunters were discovered around a camp fire. They showed no signs of injury, and nothing had been stolen. The only strange thing about the scene was the coffee pot. Curled up inside was a newt.

In the 1960s, a biologist named Butch Brodie got curious about the story. The newt in the coffee pot – known as the rough-skinned newt – has a dull brown back, but when it is disturbed, it bends its head backward like a contortionist to reveal an orange belly as bright as candy corn. Bright colors are common among poisonous animals. It’s a signal that says, in effect, “If you know what’s good for you, you’ll leave me alone.” Brodie wondered if the newts were toxic, too.

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Toxic, it turns out, doesn’t do the newts justice. They are little death machines. The newts produce a chemical in their skin called tetrodotoxin, or TTX for short, that’s made by other poisonous animals like pufferfish. Locking onto sodium channels on the surface of neurons, TTX blocks signals in the nervous system, leading to a quick death. In fact, TTX is 10,000 times deadlier than cyanide. While we may never know for sure what killed those three Oregon hunters, we do know that a single rough-skinned newt could have easily produced enough TTX to kill them, and have plenty of poison left over to kill dozens more.

Now, if the whole idea of evolution makes you uneasy, you might react by saying, “That couldn’t possibly have evolved.” Experience has shown that this is not a wise thing to say. Brodie said something different: the most plausible explanation for a ridiculously poisonous animal is that it is locked in a coevolutionary arms race with a ridiculously well-defended predator. Another biologist mentioned to him that he’d seen garter snakes dining on rough-skinned newts, and so Brodie investigated. He discovered that garter snakes in rough-skinned newt territory have evolved a peculiar shape to the receptors on their neurons that TTX would normally grab.

So these garter snakes have evolved a tolerance for quite stunning amounts of TTX.

The newts haven’t appeared on this blog before, but pufferfish have — in a discussion of cartoon #4 in a 4/10/17 posting of mine:

The cartoon is funny only if you recognize the fish as a pufferfish or blowfish, which puffs up and then blows out. On the family [of these fish], from Wikipedia

On to Death in Paradise, S3 E2 “The Wrong Man” (from 1/21/14), which you can watch in its entirety here. Synopsis:

A killer [using TTX in chocolates] murders the wrong person on a film set; the intended target needs to be identified before the killer strikes again.

The two principal actors in this episode:

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Kris Marshall (as DI Humphrey Goodman) and Sara Martins (as DS Camille Bordey)

Earlier postings about the show:

from 8/2/15, “Danny John-Jules”, about the actor (as officer Dwayne Myers) and a lot about the show

from 8/3/15, “Gary Carr”, about the actor (as officer, later sergeant, Fidel Best)

About the luminous Martins, from Wikipedia:

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Sara Martins (born 19 August 1977) is a French-Portuguese actress. She is known in France for her roles on television and in film and theatre. From 2011 she appeared as Detective Sergeant Camille Bordey in the joint British-French crime comedy-drama Death in Paradise, which is filmed in Guadeloupe, a French overseas department.

Martins was born in Faro, Portugal, and is of Cape Verdean descent. She moved to France at the age of three. She studied ballet in her youth and was the first person of African descent to join the Lyon Opera. She learned that she would be unable to advance to the Paris Opera, where the corps was expected to look alike and there were no other black dancers. Instead, she received her Baccalauréat with a theater option. After receiving a DEUG [Diplôme d’études universitaires générales] in law, at age 20 she studied at Ecole de théâtre Les Enfants Terribles in Paris. Then, she completed an acting degree at the … French National Academy of Dramatic Arts. She is fluent in Portuguese, French, and English.

 

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