An “Alien Worm” With Three Sexes Found Living in Toxic Lake

Temporarily dubbed Auanema sp., has three different sexes, can survive 500 times the lethal human dose of arsenic, and carries its young inside its body like a kangaroo.

This is as alien as it gets.

Scientists at the California Institute of Technology (Caltech) have discovered a new species of worm that thrives in the extreme environment of Mono Lake, a saline soda lake in Mono County, California, formed at least 760,000 years ago as a terminal lake in an endorheic basin.

According to a new study detailing the discovery, published in the journal Current Biology, this new species, temporarily dubbed ‘Auanema sp.’, Has three different sexes, can survive 500 times the lethal human dose of arsenic and transports its “babies” inside its body like a kangaroo.

Mono Lake, located in the Sierras of Eastern California, is three times saltier than the ocean and has an alkaline pH of 10.

Before this study, it was only known that two other species (in addition to bacteria and algae) lived in the lake: shrimp and alkaline flies. In this new work, the team discovered eight more species, all belonging to a class of microscopic worms called nematodes, which thrive in the lake and its surroundings.

The study was mainly performed in the laboratory of Professor Paul Sternberg, professor of Biology, who has had a great interest in nematodes, particularly in the ‘Caenorhabditis Elegans‘, which uses only 300 neurons to exhibit complex behaviors, such as sleeping, learning, smelling and movement.

Its simplicity makes it a useful model organism to study fundamental questions of neuroscience and also thrives easily in the laboratory under normal temperatures and pressures. As explained by Caltech experts, there are only a few extremophiles on Earth that can be studied in the lab.

Eighth really resistant species

The eight species the scientists discovered are diverse, from benign microbes to parasites and predators, all of them resistant to arsenic-laden conditions in the lake and, therefore, considered extremophiles, organisms that thrive in conditions unsuitable for most forms of life.

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The scientists compared the new ‘Auanema’ species with the sister species of the same genus and discovered that similar species also demonstrated high arsenic resistance, although they do not live in environments with high levels of arsenic. The discovery may indicate that nematodes bare a genetic predisposition for resilience and flexibility in adaptation to severe and benign environments alike. They can thrive in the most extreme environments but also in favorable ones.

“Extremophiles can teach us a lot about innovative strategies to deal with stress,” former Sternberg lab graduate students Pei-Yin Shih said in a statement. “Our study shows that we still have a lot to learn about how these thousand-cell animals have dominated survival in extreme environments.”

The scientists now want to determine if there are distinct biochemical and genetic factors that allow the survival of the nematodes and sequence the genome of ‘Auanema sp.‘ to look for genes that allow arsenic resistance.

This would lead to solving a huge problem on Earth.

Drinking water contaminated with arsenic is a major global health problem; Understanding how organisms such as nematodes treat arsenic will help answer questions about how the toxin moves and affects cells and bodies.

Via
Caltech