Worms from another world with three sexes discovered at Mono Lake

Scientists at Caltech have discovered a new worm species thriving in the extreme environment of Lake Mono. This new species, temporarily dubbed Auanema sp., Has three different sexes, can survive 500 times more than the lethal dose of arsenic to humans, and carries its young people in its body like a kangaroo.

The Mono Lake, located in the eastern sierras of California, is three times saltier than the ocean and its alkaline pH is equal to 10. Before this study, only two other species (with the exception of bacteria and seaweed) lived in the lake – shrimp brine and diving flies. In this new work, the team discovered eight other species all belonging to a class of microscopic worms called nematodes, thriving in and around Mono Lake.

The work was done mainly in the laboratory of Paul Sternberg, professor of biology in Bren. An article describing the research appears online on September 26 in the newspaper Current biology.

The Sternberg laboratory has long been interested in nematodes, in particular Caenorhabditis elegans, which uses only 300 neurons to present complex behaviors, such as sleeping, learning, feeling and moving. This simplicity makes it a useful model organism for studying fundamental questions in neuroscience. Mostly C. elegans can easily thrive in the laboratory at normal ambient temperatures and pressures.

Nematodes being considered the most abundant animal type on the planet, Pei-Yin Shih (Ph.D. 19) and James Siho Lee (Ph.D. 19), former graduate students of the Sternberg laboratory, thought they could find in the harsh environment of Mono Lake. The eight species they found are diverse and range from microbrilling parasites to parasites and predators. It is important to note that all are resistant to lake conditions filled with arsenic and are therefore considered extremophiles, organisms that develop under conditions that are unsuitable for most life forms.

By comparing the new Auanema species to sister species of the same genus, the researchers found that similar species also exhibited high resistance to arsenic, even though they did not live in arsenic-rich environments. In another surprising discovery, Auanema sp. itself has proven to be able to thrive in the laboratory under normal and not extreme conditions. Only a few extremophiles known in the world can be studied in the laboratory.

This suggests that nematodes may have a genetic predisposition to resilience and flexibility to adapt to harsh and benign environments.

"Extremists can teach us a lot about innovative coping strategies," Shih said. "Our study shows that we still have a lot to learn about how these 1,000-celled animals control survival in extreme environments."

Researchers are investigating whether there are specific biochemical and genetic factors that allow the success of nematodes and sequence the genome of Auanema sp. look for genes that can promote arsenic resistance. Drinking water contaminated with arsenic is a major concern for global health; Understanding how eukaryotes like nematodes treat arsenic will help answer questions about how the toxin travels and affects cells and the body.

But beyond human health, studying extreme species like Lake Mono nematodes helps to give a more global picture of the planet, said Lee.

"It is extremely important that we appreciate and develop a curiosity for biodiversity," he added, noting that the team was to receive special permits for its field work on the lakeshore. "The next innovation in biotechnology could be in nature – a new biodegradable sunscreen, for example, has been discovered from bacteria and extremophilic algae, we need to protect and use wildlife responsibly."

The document titled "Newly identified nematodes of extreme resistance to arsenic exposed in Mono Lake".

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