Azotosome – shell for extraterrestrial microorganisms
Chemists have come up with a bacterium that could survive on Titan
For terrestrial organisms, the conditions there are unbearable: there is no water, instead there are lakes of liquid methane, the atmosphere is not like Earth's and consists mainly of nitrogen, and the temperature on the surface is about minus 170 degrees Celsius. Astrobiologists searching for life on other planets usually do not consider such harsh conditions and are looking for planets where water is possible, and in a liquid state.
"We are not biologists or astronomers, but we have the right tools. Perhaps it even helped us, because we had no preconceived ideas about what the cell membrane should consist of. We just worked with the components that are there (on Titan), and wondered what can be made of them," explains Paulette Clancy from Cornell University, whose words are quoted on the university's website (Life 'not as we know it' possible on Saturn's moon Titan).
The membrane of the cells of terrestrial living organisms consists of phospholipids – fats and similar substances. It separates the internal structures of the cell from the external environment. Similar membranes, only empty, spontaneously form in a mixture of phospholipids with water. Such fat droplets are called liposomes.
Clancy and her colleagues modeled a cell membrane that could spontaneously assemble from those substances that exist on Titan: nitrogen, carbon and hydrogen. By analogy with liposomes, it was called the azotosome. The membrane made of acrylonitrile, a liquid toxic organic substance that is used in the production of synthetic fibers and rubber, has proven itself best. Acrylonitrile is present in the atmosphere of Titan.
The membrane turned out to be both strong and flexible – the membranes of living cells have exactly the same properties. The researchers' future plans are to see how it will behave in a methane environment and whether it is possible to find analogues of the basic cellular functions for a cell with such a membrane.
From acrylonitrile molecules to a 90 angstrom azotosome
(picture from an article in Science Advances) – VM.
The scientific article by Clancy and her colleagues Membrane alternatives in worlds without oxygen: Creation of an azotosome is published in the journal Science Advances.
Portal "Eternal youth" http://vechnayamolodost.ru03.03.2015