New Test makes searching for extraterrestrial life easier

German researchers have developed a smart, simplified method to get microbes moving, which can give the search for life on Mars and other planets a big boost.

Many astronomers are keen to find extraterrestrial life. For them, the discovery of life outside the earth would not only be scientifically groundbreaking, but it would also answer fundamental questions about our existence and the conditions for life in the universe. It is one of the biggest challenges and ambitions within astronomy and astrobiology. Yet, despite many frantic attempts, it has not yet been possible to encounter aliens. But maybe a new test will soon change that.

Chemotaxis
A promising approach is the detection of microorganisms that can move independently-a clear indication of life. When an organism reacts to a chemical by moving, we call this chemotaxis. “Chemotaxis is the smart way in which microorganisms move towards nutrients or away from hazardous substances, all in response to chemical signals,” explains Max Riekeles, researcher at the Technical University of Berlin, in conversation with Scientias.nl out. “This behavior is crucial for their survival and adaptation to various environments.”

Cinema
In the search for extraterrestrial life, Chemotaxis is a promising indication, because mobility is a powerful evidence for biological activity. “It is difficult to identify prokaryotic life only based on appearance, even with advanced microscopy, because non-living particles sometimes look the same,” says Riekeles. “However, detecting targeted movement clearly indicates that there is active mobility – an important indication of life.”

Movement
Incidentally, it is important to emphasize that not all micro-organisms actively exercise. “Some microbes rely more on passive absorption of nutrients due to diffusion,” explains Riekeles. “Whether a potential mobile microbe actually moves depends on various factors, such as temperature and the availability of nutrients (too many nutrients can lead to growth instead of mobility). Our goal is to stimulate the mobility of microbes and then to distinguish it as ‘active’ mobility, so that we can recognize and separate passive movements. ”

L-serine
To do this, Riekeles has now developed a new, simplified method with his colleagues to activate ‘chemotactic mobility’ in some of the smallest life forms on earth. The researchers used L-Serine, an amino acid that has previously called Chemotaxis in a wide range of species from all areas of life. Moreover, it is assumed that it is also present on Mars. If life on Mars has a similar biochemistry like on earth, it is quite possible that L-Serine could attract Martian microbes.

Testing
The test that the researchers developed does not use complex equipment, but revolves around a simple arrangement: an object glass with two rooms, separated by a thin, semi-permeable membrane. “We placed the microbes in one room, while we added L-Serine in the other room,” says Riekeles. “The membrane acts as a barrier that prevents passive particles (such as sand grains or mars regulatory) to move through the membrane, while actively ‘swimming’ microbes can pass through it. After a certain time we investigated the room with L-Serine under the microscope. Microbes who had successfully passed the membrane were visible as clear spots. Instead of immediately following the mobility of the microbes – a task that requires a lot of computing power – our method offers a simpler and more efficient alternative with minimal computer requirements. ”

Microbes
The team tested three different microbes – two bacteria and an archaeon. “We chose to record both a gram-positive and a gram-negative bacterium so that we could capture a wider range of microbial behavior,” says Riekeles. The microbes that were included in the study were chosen because of their impressive ability to survive in extreme conditions. This way the extremely mobile Bacillus subtilis Surviving in heavy environments and even temperatures up to 100 degrees Celsius. Pseudoalteromonas haloplanktisisolated from the ice -cold waters of Antarctica, is perfectly adapted to growing in colder environments, with a temperature range of -2.5 to 29 degrees Celsius. The Areaon Haloferax volcaniiwhich varies genetically from bacteria but exhibits similar properties, occurs naturally in extremely salty environments such as the Dead Sea. This makes it easy to survive in the most extreme conditions. “Bacteria and archaea are among the oldest life forms on earth, but they move in different ways,” says Riekeles. “By testing both groups, we can further refine the life detection methods for space missions and make it more reliable.”

It works!
The results described in Frontiers in Astronomy and Space Sciencesshowed that L-Serine attracted all three species. “We discovered that they all responded to a chemical and moved to it,” explains Riekeles. “Chemotaxis can therefore be a powerful indication of life and could help future space emissions in detecting living organisms on Mars or other planets.”

Basis
To make this method suitable for a space mission, some adjustments would be needed, says Riekeles. For example, smaller, more robust equipment would be resistant to the extreme conditions of the space, and a system that works autonomously, without the need for human intervention. “But I think our concept can form the basis for a lifetime detection tool that works according to a similar principle, using microscopy,” Riekeles argues. “Future developments can build on this idea by, for example, also using multiple rooms with different chemical attractions, instead of only L-Serine. This could activate a wider range of organisms, which increases the chance of detecting various forms of mobile life even greater. ”

Achieve more with fewer resources
In short, the newly developed test could use the behavior of microbes as a crucial tool for detecting extraterrestrial life forms, for example in the ocean under the ice -cold surface of Jupiter’s Moon Europe. “Our approach could not only make tracing life cheaper and faster, but also enable future missions to achieve more with fewer resources,” concludes Riekeles. “It could be a simple and efficient way to look for life during future Mars missions and form a valuable addition to the current techniques for observing mobility.”

But how certain is Riekeles actually that there is alien life? “This statement of course comes with a good dose of uncertainty, but I estimate the chance of finding extraterrestrial life in the next 50 years at around 50 percent – although this is actually more a feeling than a statistical estimate,” he says when asked. “If we don’t discover signs of life within our solar system (perhaps in the coming century), the search can become much more complex. Detecting and interpreting biosa signatures of exoplanets remains a challenge, often with unclear results. Yet technological breakthroughs are difficult to predict, and who knows, we may be able to find life in ways that we cannot think of yet. I am therefore curious about what the future brings. ”