Microbial ecologist Angela Oliverio of Syracuse University and her team have added a new member to the roster of heat‑loving organisms: a single‑celled eukaryote that can reproduce at 145 °F (63 °C). The organism, dubbed the “fire amoeba,” pushes the upper temperature boundary for complex cells by roughly five degrees, a shift that Oliverio likens to the breakthrough of the sub‑4‑minute mile in athletics.
Finding the fire amoeba
The discovery originated from a field expedition to Lassen Volcanic National Park in northern California, a remote park noted for its geothermal activity and recent wildfire‑driven regrowth. Graduate student Beryl Rappaport and colleagues sampled steaming water from a modest tributary of Hot Springs Creek, using extended barbecue tongs to lower sealed vials into the hot flow. Back in the laboratory, microscopy of the collected water revealed a motile cell that elongated, contracted, and reshaped itself in a manner reminiscent of “hot yoga.” The movement pattern confirmed the organism as an amoeba.
Further testing showed that the amoeba could not only remain active but also divide at temperatures up to 145 °F. It continued to move at 147 °F (64 °C) and survived brief exposure to water as hot as 158 °F (70 °C). These thresholds constitute a new record for any eukaryotic microbe, which previously lagged behind bacterial and archaeal extremophiles that thrive at or above the boiling point of water.
Heat‑tolerant biology
Genomic analysis identified the organism as a distinct species, formally named Incendiamoeba cascadensis, meaning “fire amoeba of the Cascade mountain range.” Comparison with genomes of other amoebae revealed adaptations that stabilize proteins and cellular membranes under high‑temperature stress. Unlike many extremophiles that streamline their genomes to compete with bacteria, the fire amoeba possesses a comparatively larger genome, suggesting a different evolutionary strategy.
Evolutionary biologist Debashish Bhattacharya, who was not involved in the study, noted that the larger genome represents an alternative path to thermal resilience. He explained that while genome reduction is common among heat‑tolerant microbes, the fire amoeba appears to have retained more genetic material, possibly to support complex cellular functions at extreme temperatures.
Potential applications
The findings have implications beyond basic biology. Oliverio argues that understanding how a eukaryote endures such heat could inform the development of crops capable of withstanding higher temperatures, as well as the design of pharmaceuticals that remain stable across broader temperature ranges. The discovery also expands the scope of astrobiological searches by illustrating that complex life can persist under conditions previously thought prohibitive.
While translating exotic organisms into practical technologies remains challenging, Bhattacharya cautioned that breakthroughs are possible when unique traits are identified. He emphasized that the fire amoeba’s distinct genomic architecture may harbor novel genes or pathways useful for biotechnological innovation.
Oliverio hopes the documentation of Incendiamoeba cascadensis will inspire further exploration for heat‑tolerant eukaryotes. “Perhaps the upper temperature record will be broken again soon,” she said, encouraging other researchers to investigate understudied habitats where extreme conditions may conceal additional biological surprises.
Norman Pearlstine is the Executive Editor and Co-Founder at News Raise. With over two decades of experience across financial journalism, corporate governance, and market analysis, Norman leads the editorial direction and ensures strict adherence to journalistic accuracy and ethics.
