Scientists reported the discovery in an article published in the journal Cell. The new species of amoeba was found in the hot springs of Lassen Volcanic National Park in northern California, and it occurs in several areas of the park.
According to the researchers, Incendiamoeba cascadensis lives in water with a temperature of 49–65 degrees. In laboratory experiments, the amoeba grew and divided indefinitely at temperatures up to 63 degrees.
The authors of the study noted that most living things on Earth can exist only within a narrow temperature range, where water remains liquid and proteins retain their structure and function. Some microbes living near hot springs on the ocean floor have adapted to temperatures above 42–43 degrees, and some microbes, according to scientists, are capable of living at about 120 degrees.
For eukaryotes, which include protozoa and all multicellular life, this limit was considered significantly lower: around 60 degrees for some fungi and red algae. Against this backdrop, the new amoeba has set a record for complex cellular organisms.
Associate professor Angela Oliverio of Syracuse University in the United States called the find important because it expands our understanding of what is possible in biology and makes this amoeba especially interesting to study. She also suggested that there may be other eukaryotic extremophiles capable of living at even higher temperatures.
Scientists hope that further study of DNA will help explain the amoeba's survival mechanism in extreme heat. They also hope that the already decoded genomes of unicellular protozoa will help in the search for other eukaryotic extremophiles.
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