The creature that refuses to burn: the "fire amoeba" that broke the boundaries of life

Scientists have discovered a new microscopic amoeba in hot springs in California, dubbed the "fire amoeba," capable of reproducing at 63 degrees Celsius and surviving exposure to 70 degrees. The discovery expands knowledge about the limits of life for complex organisms and may aid in developing heat-resistant crops and cells.

Scientists have discovered a microscopic single-celled organism in hot springs in California, previously unknown, dubbed the "fire amoeba," which has broken the temperature record for where complex life can exist and reproduce. The amoeba belongs to eukaryotes — the group of organisms whose cells contain a nucleus and complex internal structures, which also includes animals, plants, and fungi. Until now, temperatures near 60 degrees were considered the upper limit for such organisms to reproduce. The researchers found that the fire amoeba thrives especially at temperatures of 55–57 degrees, but continues to reproduce up to 63 degrees. Experiments also showed it can cope for a limited time with a temperature of 70 degrees: under these conditions it changes shape, creates an external protective layer, and can recover once the temperature drops. Genetic tests revealed a relative abundance of genes related to protein maintenance, genome stability, and DNA damage repair. The researchers estimate the discovery may have practical implications, similar to the bacterium Thermus aquaticus discovered in Yellowstone, whose enzymes are used in DNA copying. Possibilities include developing methods for engineering heat-resistant cells and agricultural crops. However, researcher Beryl Rapaport explained that even the new creature is not protected from climate change — further warming could dry up the geothermal water sources where it lives.