Remember the Blob, a gelatinous alien monster that could devour anything in its path. Amoebae do the same: they form ‘false legs’ by directing their cytoplasm and engulf their prey, eventually devouring it. The Blob was frozen solid, and we must be glad that they did. Because now, scientists have discovered a microscopic ‘blob’, an amoeba, that can withstand temperatures over 63°C (145.4°F), which disrupts the functioning of most complex cells.
Eukaryotes, or cells with well-defined internal structures and a nucleus, include animal and plant cells. These cells are more fragile than prokaryotes, such as bacteria, and other organisms that lack a nucleated nucleus, and are less resilient to high temperatures.
Angela Oliverio, a microbiologist at Syracuse University in New York, advocates a review of what’s possible for an eukaryotic cell, following this discovery. Oliverio and fellow Syracuse microbiologist Beryl Rappaport were part of a team that discovered the organism at Lassen Volcanic National Park in northern California’s Cascade mountain range. This amoeba, named Incendiamoeba cascadensis, literally translates to “fire amoeba from the cascades.”
Lassen is renowned for acid lakes and incandescent geothermal pools, but this amoeba has been found in a pH-neutral ‘hot stream’— which is pretty drab when compared to other features of this park, says Rappaport.
Water samples from the streams appeared devoid of life; however, upon supplying nutrients and culturing at 57°C (135°F), researchers observed a growing population of amoebae in the sample. It broke the previous record for thriving at 60°C (140°F), divided at 63°C (145.4°F), and moved at slightly higher temperatures. The amoeba formed dormant cysts at 70°C (158°F) that could reactivate at lower temperatures.
Bacteria and archaeans are much hardier, think of the “Wet Bandits” from Home Alone. The archaeal Methanopyrus kandleri holds the record for the highest temperature at which life has been observed, at 122 °C. Many algal and fungal species can survive higher temperatures, whereas mammals, including humans, have cells that are adapted to survive around 43°C (109.4°F).
Julia Van Etten, an evolutionary biologist at the University of Maryland in College Park, says, “This group discovered one that’s doing something we didn’t know eukaryotes were capable of. So what else is out there?”
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