Fire Amoeba (Incendimoeba cascadensis) Photo from https://www.sciencenews.org/article/fire-amoeba-record-breaking-heat

Dear Readers, this week scientist  Angela Oliverio of Syracuse University revealed that an amoeba had been found which could survive temperatures of 70 degrees Celsius (158 degrees Fahrenheit), ten degrees Celsius higher than the previous record. This is really quite something. One of the main problems with high temperatures for most organisms is that at a certain point, the structure of the proteins in the body starts to unravel, meaning that they can’t do their essential jobs – proteins are involved in practically every major function in the body. This is known as ‘denaturing’, and to see a classic example, just crack an egg into a hot frying pan – as the proteins in the egg white unfold and become ineffective, they turn white. So to find a complex organism that can live in temperatures this high (found in the hot springs of Lassen Volcanic National Park in California) was quite something. In the photo above, the amoeba is splitting into two organisms, something that stops at 63 degrees Celsius. At 64 degrees Celsius, the amoeba stops moving and forms itself into a protective cyst but is still clearly alive.

Amoebae are quite advanced animals – they are eukaryotes, which means that their cells have a nucleus, just as ours do. This particular species is a predator of the heat-loving (thermophilic) bacteria which live in the hot spring, Whilst simpler organisms which don’t have a nucleus can survive at even higher temperatures – Methanopyrus kandlerii, for example, can survive at up to 122 degrees Celsius – the discovery of a higher organism which can live at such high temperatures gives a lot of potential material for study. How do they do it?

One thing that the amoeba seems to have in abundance is a range of molecules called heat shock proteins – these help to stabilise unravelling proteins, including those that live in cell membranes and are essential for transporting vital chemicals through the cell wall. DNA can also be damaged by high temperatures, but as the temperature goes up, more DNA repair molecules are secreted. Interestingly, both advanced and simpler organisms have very similar heat-resistance mechanisms, meaning they probably evolved separately when similar stresses were applied. All in all, this extends the possibilities for where life might exist, both here and (potentially) on other planets too.

The New Scientist article is here.

The research paper is here.