Scientists discover amoeba that survives where most life cannot
A new species of amoeba has been discovered that lives and reproduces at temperatures up to 63 degrees Celsius—the highest ever documented for a eukaryotic organism (that is, one possessing cellular organelles, including a nucleus containing DNA).
Named Incendiamoeba cascadensis, meaning “fire amoeba from the cascades,” it was found in the boiling waters of Lassen Volcanic National Park in California, CE Report quotes ANSA.
Its profile, which opens new possibilities for the search for extraterrestrial life, is shared on the bioRxiv platform by biologists from Syracuse University in New York.
Their laboratory experiments show that this new unicellular organism does not grow below 42 degrees. Its optimal temperature range is between 55 and 57 degrees. Cell division (mitosis) was observed at 58 and 63 degrees. Incendiamoeba cascadensis remains active at 64 degrees, thus breaking the previous amoeba record of 57 degrees (set by Echinamoeba thermarum) and even surpassing the long-assumed 60-degree limit for eukaryotic growth.
At 66 degrees, I. cascadensis begins forming protective cysts, a strategy that allows it to enter dormancy to survive harsh conditions. Protective cysts also formed at 25 degrees, an unusually high lower limit, considering that most eukaryotes prefer temperatures well below that value, and many thrive best at room temperature. Further experiments revealed that the amoeba stops moving at 70 degrees but can revive when temperatures drop. Only at 80 degrees does I. cascadensis die.
Genome analysis provided clues as to how this tiny organism withstands such extreme conditions. It possesses adaptations that allow it to send signals rapidly and react to heat, as well as a higher number of particularly heat-resistant proteins and special proteins (“chaperones”) that protect it from thermal stress.
