NASA · Space

NASA-Funded Research Discovers Complex Life Thriving in Extreme Heat

Scientists have identified a complex organism, Incendiamoeba cascadensis, that can reproduce at temperatures previously thought impossible for eukaryotes, expanding the known boundaries of life.

An amoeba, dubbed the fire amoeba, discovered in California's Lassen Volcanic National Park, can reproduce by division at 145°F (63°C), setting a new record for eukaryotes. It remains active up to 147°F (64°C) and can recover from brief exposure to 158°F (70°C), though 176°F (80°C) is lethal.

This discovery challenges the assumption that complex eukaryotic cells, with their delicate internal structures like the nucleus and organelles, cannot withstand such high temperatures. Previously, the upper limit for eukaryotes was around 140°F (60°C).

The research, published in Cell, is significant for astrobiology, as studying extremophiles helps scientists understand the potential for life on other planets with harsh conditions.

The fire amoeba's survival mechanisms include genes that stabilize DNA and protect against breakdown. Increased gene expression for protein folding and positively charged proteins also contribute to its heat tolerance.

The study sequenced the amoeba's genome, revealing strategies for surviving extreme heat. Researchers found similar DNA fragments in geothermal samples from New Zealand and Yellowstone, suggesting related thermophilic amoebas may exist globally.

While this finding expands the possibilities for complex life in extreme environments, survival depends on a complete ecosystem, including factors like acidity, oxygen, pressure, water, and food, not just temperature.

This research enhances our understanding of where and how complex life can persist, both on Earth and potentially beyond, by demonstrating the resilience of eukaryotic cells in high-temperature environments.

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