Incendiamoeba cascadensis: amoeba that divides at 63°C

American researchers have found an amoeba in a geothermal spring in Lassen Volcanic National Park, California, that lives and reproduces at 63°C, Kursor reports, citing Science Alert. cursorinfo.co.il The organism was named Incendiamoeba cascadensis, the "fire amoeba of the Cascades". cursorinfo.co.il

Heat limit for eukaryotes

Eukaryotes are organisms whose cells contain a formed nucleus and organelles. The group includes animals, plants, fungi and protists. Until now they were considered highly sensitive to strong heat, and 60°C was regarded as their upper temperature limit. cursorinfo.co.il

Prokaryotes, meaning bacteria and archaea, tolerate much harsher conditions. The archaeon Methanopyrus kandleri, which lives near deep-sea hydrothermal vents, stays viable at 122°C. cursorinfo.co.il For eukaryotes, the discovery of the Cascade amoeba moves the previously accepted boundary of heat tolerance. cursorinfo.co.il

Laboratory tests of endurance

In laboratory experiments, a team led by biologist Angela Oliverio determined the limits of the new species. At 63°C the amoeba continued asexual division (mitosis). Above this threshold, cell growth stopped completely. cursorinfo.co.il

At temperatures above 64°C the organism entered a protective state: it curled its single-celled body into a dense ball and formed a cyst. cursorinfo.co.il After brief exposure to 70°C, the amoeba was able to recover and return to normal growth once cooled to 60°C. cursorinfo.co.il

The absolute lethal limit for the species was 80°C, after which cellular structures are destroyed irreversibly. cursorinfo.co.il The researchers suggest that other eukaryotes capable of surviving even higher temperatures may be hiding in unexplored corners of the planet. cursorinfo.co.il

Incendiamoeba cascadensis, a new amoeba, divides at 63°C in a California hot spring

Heat limit for eukaryotes

Laboratory tests of endurance

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