When experts warn of aliens posing a threat to life on Earth, we think of an advanced species destroying our planet via futuristic weaponry. However, a new study has revealed microorganisms from deep space could pose the biggest threat. The coronavirus pandemic has shown that disease can bring life to a standstill on Earth, and if an unknown disease were to travel to our planet via the likes of a meteorite, the results could be devastating.
Life-forms on Earth are based on amino acids, but these amino acids could be slightly different to the ones potentially found in space.
Researchers from the universities of Aberdeen and Exeter tested how mammal immune cells responded to peptides (combinations of amino acids) containing two amino acids that are rare on Earth but are commonly found on meteorites.
The study conducted in mice – which have a similar immune response to humans – showed that mammals have a “less efficient” response to peptides commonly found on meteorites.
Researchers examined the reaction of T cells, which are key to immune responses, to the amino acids isovaline and α-aminoisobutyric acid.
The response was weak, with T-cell activation levels of 15 percent and 61 percent – compared to 82 percent and 91 percent when exposed to peptides made entirely of amino acids that are common on Earth.
Professor Neil Gow, Deputy Vice-Chancellor (Research and Impact) at the University of Exeter, said: “The world is now only too aware of the immune challenge posed by the emergence of brand new pathogens.
“As a thought experiment, we wondered what would happen if we were to be exposed to a microorganism that had been retrieved from another planet or moon where life had evolved.
“Some very unusual organic building blocks exist outside of the planet Earth, and these could be used to make up the cells of such alien microbes.