NASA-Funded Research Finds Complex Life Defying Record Heat

6 min read NASA-Funded Research Finds Complex Life Defying Record Heat This video shows Incendiamoeba cascadensis motility at 60ºC. When pushed to its limits in the lab, I. cascadensis can remain partially active at 150.8 degrees Fahrenheit (66 degrees Celsius) and can recover from exposure to a staggering 158 degrees Fahrenheit (70 degrees Celsius) for five minutes. However, 176 degrees Fahrenheit (80 degrees Celsius) proved to be too much for the amoeba to come back from. Beryl Rappaport Lee esta historia en español aquí . NASA-supported scientists have discovered an organism that lives at extreme temperatures previously thought impossible for complex life. High temperatures can cause the destruction of necessary cell components, which is a big problem for cells with complex parts like a nucleus encasing delicate genetic information. In the heated waters of California’s Lassen Volcanic National Park, a team of scientists observed an amoeba that can reproduce by division at an astonishing 145 degrees Fahrenheit (63 degree Celsius), setting a record for the upper temperature limit for all known eukaryotes. Incendiamoeba cascadensis, also dubbed the fire amoeba, stops reproducing above 145 degrees Fahrenheit but is still active, moving around to search for food at up to 147 degrees Fahrenheit (64 Celsius). The previous limit of 140 degrees Fahrenheit (60 Celsius) for eukaryotes was set by a few species of fungi and red algae. The results were published on Tuesday in the journal Cell . Astrobiologists have long studied the boundaries of life’s survival on Earth to determine how organisms might live on other worlds like Mars where conditions are less hospitable than our home planet. Organisms that endure at the edges of habitability under extreme temperature, pH levels, radiation, and other environmental conditions are known as extremophiles. Studying them helps scientists understand what life as we know it is capable of. Extremophiles also produce unique proteins that can have promising uses in biotechnology, from industrial applications to medicine. Previous extremophile research has mostly focused on single-celled bacteria and archaea. The new study shows that the more complex cells of eukaryotes might be more durable than previously thought and could even help scientists understand locations in the universe where complex life could survive. Complex life on Earth Life on Earth is broadly divided into two categories, prokaryotes and eukaryotes. Prokaryotes are single-cell organisms that do not have a nucleus or membrane-bound organelles inside their single cell. This means that they have less cellular ‘machinery’ that can be damaged by extremes, such as blistering heat, bitter cold, caustic acidity, or damaging radiation. Organisms that live in extreme heat are known as thermophiles. To be a true ‘heat-loving’ thermophile, the organism must be able to replicate, move, eat, and survive above 113 degrees Fahrenheit (45 degrees Celsius). Prokaryotes include bacteria and archaea, with archaea being particularly adept at surviving extremes. Because of their relative simplicity, scientists also believe that prokaryotes were the first forms of life to appear on Earth, billions of years ago when the environment of our planet was much more inhospitable than it is today. Eukaryotes are more complicated organisms that are thought to have evolved later in the history of life on Earth. These organisms have a separate cell nucleus inside their cells that contains fragile genetic information. Eukaryotes also contain membrane-bound organelles, such as mitochondria and endoplasmic reticulum. These organelles are like mini cellular machines that perform specific functions. Eukaryotes include a wide span of life, from single-celled algae to multicellular organisms like plants and human beings. Complexity in Extreme Heat High temperatures lead to the breakdown of proteins and other biomolecules that living cells need to function. Heat also can cau