A geothermal amoeba sets a new upper temperature limit for eukaryotes

2025/11/24 by Hannah Rappaport, Natalie A. Petek-Seoane, Tomáš Tyml +18 · 3 voices · 3 citations
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Bacteria #Gene #Genome #Geothermal gradient #Legionella and Acanthamoeba research #Limit (mathematics) #Mitosis #Protist diversity and phylogeny #Tardigrade Biology and Ecology

paper · pdf · doi:10.1101/2025.11.24.690213

published in bioRxiv (Cold Spring Harbor Laboratory) (Cold Spring Harbor Laboratory)

openalex publication_date 2025/11/24 · openalex created_date 2025/11/25 · openalex updated_date 2026/08/01

Abstract

The study of temperature limits has transformed our knowledge of the boundaries of life but has been largely focused on bacteria and archaea. We isolated a novel geothermal amoeba, Incendiamoeba cascadensis, that divides at 63°C (145.4°F), establishing a new record for the upper temperature limit across all eukaryotes. We demonstrated cellular proliferation with growth experiments and visualized mitosis via expansion microscopy. Using high-temperature live-cell imaging, we quantified movement up to 64°C. We assembled the genome of I. cascadensis and using comparative genomics found an enrichment of genes related to proteostasis, genome stability, and sensing the external environment. Taken together, our findings challenge the current paradigm of temperature constraints on eukaryotic cells and reshape our understanding of where and how eukaryotic life can persist.

Citations

• AlphaFold Protein Structure Database and 3D-Beacons: New Data and Capabilities
• CONFIDENCE LIMITS ON PHYLOGENIES: AN APPROACH USING THE BOOTSTRAP

Cited by

• ‘Fire amoeba’ survives in hotter conditions than any other complex cell
• The Maximum Growth Temperature for Eukaryotes Is Thermodynamically Driven but Ecologically Contingent [europepmc]

Discussions

• Introducing ** Incendiamoeba **, a eukaryote that can live at temperatures well beyond what we thought possible. 63C!! Read @hbrappap.bsky.social thread to see what we’ve already started to learn fro [bsky, 72 points, 5 comments]
• Ooh, I got a hot preprint - literally! A new record-breaking eukaryote, Incendiamoeba cascadensis, that can survive and reproduce in 63°C! doi.org/10.1101/2025... [bsky, 13 points, 1 comments]
• Yes, these movies can be downloaded from the supp materials here! doi.org/10.1101/2025... [bsky, 9 points, 2 comments]

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