Astrobiologists from the United States conducted a unique experiment to prove that ordinary Escherichia coli and some strains of yeast can normally live and reproduce in the atmosphere, similar in composition to the matter of Jupiter and other giant planets. Their findings were published in an article in the journal Nature Astronomy.
"In our experiment, the microbes lived in an atmosphere of pure hydrogen, however, in real planets the air will contain other substances. The fact that simple living creatures, such as E. coli and yeast, much more complex organisms, can live and thrive in such extreme conditions, greatly expands the field of search of extraterrestrial life," the researchers commented.
Microbes-extremophiles capable of living at high and low temperatures, with a constant lack of food and oxygen, have long attracted the attention of scientists. On the one hand, they are considered a kind of analogue of what organisms can live on Mars and other planets. On the other, many of them have a very unusual metabolism, as well as the related set of enzymes and other devices not typical for other representatives of life. They are particularly interesting to physicians, chemists and biologists, since the study of these unusual features of extremophiles can bring a lot of practical and useful discoveries.
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American studies of planetary scientists
A group of scientists under the leadership of Sara Seager, Professor of Massachusetts Institute of technology (MIT) in Boston (USA), wondered are there on Earth microbes can live in an atmosphere composed of pure hydrogen.
Such conditions as now suggested by the astronomers, may be characteristic not only for analogues of Jupiter and other gas giants outside the Solar system, but for many supertall, large rocky planets in the atmosphere which may not contain significant amounts of oxygen and its compounds.
On Earth, as noted by Seeger and colleagues, there are many germs from the so-called methanogens are able to live in an atmosphere composed of 80% hydrogen and 20% carbon dioxide. On the other hand, to date no one has tested whether bacteria or other microorganisms to exist in 100% hydrogen atmosphere.
American scientists have corrected this defect, creating an installation, simulate the conditions in the upper atmosphere of gas giants, consisting of helium, hydrogen, nitrogen, carbon dioxide and other gases. It allows scientists the flexibility to vary the amount of these substances in the nutrient medium and to monitor how these changes react germs.
To test this system, biologists have chosen two well-studied microorganism, conventional E. coli and yeast. And the bacteria, and mushroomsit can live without access to oxygen, but in the past nobody checked whether they are able to endure extreme conditions, including life in a 100% hydrogen atmosphere.
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life in an atmosphere of pure hydrogen
Initially, biologists didn’t expect to get a positive result, however, to their great surprise, bacteria and fungi not only did not die in such conditions, but quickly adapted to life in such conditions. Their metabolism and reproduction rate fell, but E. coli and yeast have successfully switched to oxygen-free metabolism type, able to operate normally in a hydrogen atmosphere.
All this, according to Seager and her colleagues, indicates that life can appear not only on earth-like planets with lots of oxygen, but also on many other worlds, whose atmosphere consists mainly of hydrogen or its mixture with methane and ammonia. Now, astrobiologists are trying to understand how it is possible to detect the traces of such life, by studying the gases that produce yeast and E. coli, living in a hydrogen atmosphere.
