Two if by land? Biologists discover deadly TTX toxin in two terrestrial species

Jun 25, 2014 by Mary-Ann Muffoletto
Flatworm subdues much larger earthworm prey using deadly neurotoxin
A flatworm (Bipalium adventitium) subdues its prey, an earthworm 10 times larger in weight, by using its neurotoxin, tetrodotoxin. Biologists report the first evidence of the lethal compound in two terrestrial species. Credit: Utah State University

Adventurous fans of the sushi delicacy fugu – or pufferfish – already know the food's intoxicating tingle comes from tetrodotoxin, a potent neurotoxin that's deadly beyond small doses. What these diners and others didn't know, until now, is the toxin is found in organisms living out of water.

California State University, Bakersfield biologist Amber Stokes and colleagues report, for the first time, confirmation of the lethal compound, known as TTX, in terrestrial species.

With Utah State University colleagues Lorin Neuman-Lee, Charles Hanifin, Susannah French and Edmund "Butch" Brodie, Jr., along with Peter Ducey of the State University of New York, Cortland; Mike Pfrender of the University of Notre Dame and Edmund Brodie, III, of the University of Virginia, Stokes published findings of two flatworm species, Bipalium adventitium and Bipalium kewense, with TTX in the June 25, 2014, open access journal PLoS One.

The team's research was supported by the National Science Foundation.

"This study is the first to show tetrodotoxin in a terrestrial invertebrate," says Brodie, Jr., professor in USU's Department of Biology and the USU Ecology Center and Stokes' advisor during her graduate studies.

Tetrodotoxin acts by blocking electrical signals in both nerve and muscle tissue, resulting in paralysis and, in sufficient doses, death. Brodie has long studied varied species of North American garter snakes that have evolved an amazing resistance to TTX found in newts, a favorite food of the snakes.

"TTX is thought to originate in marine bacteria and may accumulate in certain organisms, such as pufferfish, through ingestion," Stokes says. "Some organisms may also produce it, but the origins and ecological functions of toxin in most taxa remain mysterious."

Stokes and her colleagues found the two flatworms in their study use TTX to subdue and feast on much larger earthworm prey.

"We also found the toxin in the egg capsules of one of the species," she says. "This may indicate a further role of TTX as a way of protecting offspring from opportunistic predators."

The authors say the study's findings will allow further investigation of the production or accumulation of the neurotoxin in terrestrial systems.

"This is really a novel finding," Stokes says. "These add to our current knowledge and allow us further opportunities to explore where TTX comes from and how it is produced biochemically."

Explore further: Researchers learn how botulism-causing toxin enters bloodstream

More information: Two Terrestrial Flatworm Species (Bipalium adventitium and Bipalium kewense). PLoS ONE 9(6): e100718. doi:10.1371/journal.pone.0100718

add to favorites email to friend print save as pdf

Related Stories

Mediterranean Sea invaded by alien species

May 23, 2011

More than 900 new alien species have been encountered in the coastal environments of the eastern Mediterranean Sea in recent decades, including the poisonous pufferfish. The invasion of alien species has had ...

Gritti-Stokes amputations beneficial for trauma patients

Apr 24, 2012

(HealthDay) -- The Gritti-Stokes amputation procedure is beneficial and appears to be safe for patients in a trauma setting, according to a study published in the April 4 issue of The Journal of Bone & Jo ...

Recommended for you

New hope for beloved family pets

15 hours ago

Nearly one out of four dogs will develop cancer in their lifetime and 20 per cent of those will be lymphoma cases.

User comments : 0