Toxin-Producing Bacteria Can Make This Newt Deadly
upstart writes in with an IRC submission for Soybull:
Toxin-producing bacteria can make this newt deadly:
Some newts living in thewestern United States are poisonous, perhaps thanks to bacteria living on theirskin.
Rough-skinned newts usetetrodotoxin - aparalytic neurotoxin also found in pufferfish and the blue-ringed octopus - asa defense against predators. But rather than making the toxin on their own, theamphibians (Taricha granulosa) may relyon microbes to produce it for them,researchers report April 7 in eLife.It is the first time that researchers have found tetrodotoxin-producingbacteria on a land animal.
Tetrodotoxin,or TTX, prevents nerve cells from sending signals that tell muscles to move (SN: 6/26/14). When ingested in low doses,the toxin can cause tingling or numbness. High amounts can trigger paralysisand death. Some newts harbor enough TTX to kill several people.
Marine animalsincluding pufferfish get TTX from bacteria living in their tissues or by eatingtoxic prey. It was unclear how rough-skinned newts acquire the lethal chemical.Previous work in 2004 had hinted that the newts didn't have thetoxin-producing bacteria on their skin.Newts also didn't appear to get TTX through their diet, which led scientists tothink that the animals might make the toxin themselves.
But TTX isa complicated molecule to make, says Patric Vaelli, a molecular biologist atHarvard University. It seemed unlikely that newts would be able to do it whenno other known animal can.
[...] But the finding adds a microbial player to an evolutionary arms race that pits newts against garter snakes (Thamnophis sirtalis). Some snakes living in the same regions as toxic newts have developed resistance, allowing the predators to feast on TTX-laden prey. It's possible that in response, Pseudomonas bacteria become more abundant on newts over time to make the animals more toxic, and put evolutionary pressure back on snakes to evolve higher levels of resistance, Vaelli says.
Citations:
P. Vaelli et al. The skin microbiome facilitates adaptive tetrodotoxin production in poisonous newts. eLife. Published online April 7, 2020. doi: 10.7554/eLife.53898.
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