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December 5, 2025<\/p>\n
3 min read<\/p>\n
Add Us On Google<\/span>Add SciAm<\/span><\/span><\/p>\n Newly Discovered \u2018Fire Amoeba\u2019 Pushes the Boundaries of Life on Earth<\/p>\n It was thought that complex cells couldn\u2019t survive above a certain temperature, but a tiny amoeba has proven that assumption wrong<\/p>\n By Andrea Thompson edited by Sarah Lewin Frasier<\/span><\/p>\n Incendiamoeba cascadensis (meaning \u201cfire amoeba … from the Cascades,\u201d according to a recent preprint paper) is seen moving around in a zoomed-in microscopic view.<\/p>\n \u201cA Geothermal Amoeba Sets a New Upper Temperature Limit for Eukaryotes,\u201d by H. Beryl Rappaport et al. Preprint posted to bioRxiv on November 24, 2025 (CC BY-NC-ND 4.0)<\/p>\n A tiny amoeba has broken a pretty big record.<\/p>\n The newly discovered species of single-celled organism can divide and reproduce at a piping hot 63 degrees Celsius (145 degrees Fahrenheit), higher than any other known complex form of life. The discovery\u2014described in a preprint study on the server bioRxiv and not yet peer-reviewed\u2014\u201cpushes the boundaries of our understanding of life\u2019s limits on Earth and the implications for life beyond Earth\u2014where else and how else life might be able to take hold and thrive,\u201d says microbial ecologist and astrobiologist Luke McKay, who was not involved with the new study.<\/p>\n Much of the existing research into extremophiles\u2014life-forms that thrive at extreme temperatures, acidity levels or other environmental conditions\u2014has concentrated on bacteria and archaea that are simpler in their biology, lacking a nucleus or membrane-bound cell organelles. The record holder for withstanding high temperature by any organism is an archaean, Methanopyrus kandleri, which can grow at temperatures of 122 degrees C (nearly 252 degrees F). The most heat-loving bacteria, Geothermobacterium ferrireducens, can grow at temperatures up to 100 degrees C (212 degrees F).<\/p>\n If you’re enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.<\/p>\n But conventional wisdom since the early 1970s had been that eukaryotes\u2014organisms with a cell nucleus, from amoebas to animals\u2014would not be able to cope with high temperatures as readily given their more complex biology. High temperatures can, for example, cause the proteins necessary for life to fall apart. It was thought that eukaryotes would have an upper temperature limit of 62 degrees C, and they had only been shown to tolerate temperatures of up to 60 degrees C.<\/p>\n Lassen Volcanic National Park.<\/p>\n To explore the world of eukaryote extremophiles, Syracuse University microbiologist Angela Oliverio and her graduate student Beryl Rappaport took samples from Lassen Volcanic National Park, in the Cascade mountain range in northern California, and cultured them in flasks back in their lab. After a few weeks of growth, researchers spotted the never-before-seen amoeba species in flasks that had been kept at temperatures similar to those of the stream it was found in. As the researchers notched up the temperature, the amoeba, dubbed Incendiamoeba cascadensis (meaning \u201cfire amoeba … from the Cascades,\u201d according to the preprint), kept on going. It was able to replicate itself in temperatures of up to 63 degrees C, remain active at up to 64 degrees C, and form a protective coating and survive encased in it at up to 70 degrees C (reawakening when the temperature was lowered again). \u201cOur minds were kind of blown at that point,\u201d Oliverio says.<\/p>\n The researchers also sequenced the amoeba\u2019s genome and looked at its proteome, the proteins its genes are predicted to produce. Their findings suggest the proteins it uses have a higher average melting temperature than those of its nearest amoeba relative.<\/p>\n \u201cThe difference between 60 degrees C and 63 degrees C may sound small but represents a relatively large shift in our current understanding of eukaryotic limits,\u201d says McKay, who works at the biotech research company Symbiotic Biosystems.<\/p>\n Credit: \u201cA Geothermal Amoeba Sets a New Upper Temperature Limit for Eukaryotes,\u201d by H. Beryl Rappaport et al. Preprint posted to bioRxiv on November 24, 2025 (CC BY-NC-ND 4.0); Aerial Filmworks\/Getty Images<\/p>\n The finding has implications beyond understanding wonky biology because understanding how such organisms survive high heat can help researchers develop heat-tolerant proteins and enzymes for other applications. \u201cWhy would I care about an amoeba in a random national park?\u201d Oliverio says. \u201cWell, your laundry detergent might be improved.\u201d<\/p>\n But she dwells more on the existential implications: \u201cIt raises a lot of interesting questions about what are the constraints\u201d on life, she says. \u201cAnd we have really no idea…. We sampled the stream and got this amoeba from one geothermal area. There could be hotter things out there. There probably are.\u201d<\/p>\n If you enjoyed this article, I\u2019d like to ask for your support. Scientific American<\/span> has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.<\/p>\n I\u2019ve been a Scientific American<\/span> subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm <\/span>always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.<\/p>\n If you subscribe to Scientific American<\/span>, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.<\/p>\n In return, you get essential news, captivating podcasts, brilliant infographics, can’t-miss newsletters, must-watch videos, challenging games, and the science world’s best writing and reporting. You can even gift someone a subscription.<\/p>\n There has never been a more important time for us to stand up and show why science matters. I hope you\u2019ll support us in that mission.<\/p>\n","protected":false},"excerpt":{"rendered":" December 5, 2025 3 min read Add Us On GoogleAdd SciAm Newly Discovered \u2018Fire Amoeba\u2019 Pushes the Boundaries of Life on Earth It was thought that complex cells couldn\u2019t survive above a certain temperature, but a tiny amoeba has proven that assumption wrong By Andrea Thompson edited by Sarah Lewin Frasier Incendiamoeba cascadensis (meaning \u201cfire<\/p>\n","protected":false},"author":1,"featured_media":36265,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[50],"tags":[20283,8289,2830,20282,77,337,2309],"class_list":{"0":"post-36264","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-amoeba","9":"tag-boundaries","10":"tag-complex","11":"tag-extremophile","12":"tag-fire","13":"tag-life","14":"tag-pushes"},"_links":{"self":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/36264","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=36264"}],"version-history":[{"count":0,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/posts\/36264\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=\/wp\/v2\/media\/36265"}],"wp:attachment":[{"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=36264"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=36264"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/naijaglobalnews.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=36264"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}On supporting science journalism<\/h2>\n
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