Efforts to find an alien life can be boosted by simple tests that drive microorganisms

Finding life in space is one of the great efforts of humanity. One approach is to find motile microorganisms that can move independently. This is an ability that is a strong hint in life. When movement is induced by a chemical and the organism moves accordingly, it is known as chemotactic.

Currently, German researchers are developing new, simplified methods for inducing chemotactic motility in some of the Earth’s smallest living beings. They published their results at the frontiers of astronomy and space science.

Max Rieckeles, a researcher at the Berlin Institute of Technology, said: “The movement known as chemotaxis can be a powerful indicator of life and can guide future space missions looking for creatures on Mars and other planets.”

Extreme survivor

The species included in this study were selected for their ability to survive in extreme environments.

In the form of spores, the highly motile Bacillus subspecies can withstand extreme conditions and temperatures up to 100°C. Separated from the Antarctic seas, Pseudoalteromonas haloplanktis has the aptitude to grow in cold environments from -2.5° to 29°C.

Archaeon haloferax volcanii (H. volcanii) belongs to a bacterial-like group, but is genetically different. Its natural habitat contains the Dead Sea and other high saline, making it well adapted to withstand extreme conditions.

“Bacteria and archaea are two of the oldest lives on the planet, but they moved differently and evolved motor systems independently of each other,” explained Riqueles. “Testing both groups will allow for more reliable methods of life detection for space missions.”

L-serine, the amino acid that researchers used to drive these species, has previously been shown to cause chemotaxis in a wide range of species from all areas of life. It is believed to exist on Mars. If life on Mars has similar biochemistry to life on Earth, it is plausible that L-serine can attract potential Martian microbes.

Migrating microorganisms

The results showed that L-serine works as an attractor for all three types. “In particular, the use of H. volcanii is the source of potential lifeforms that can be detected using chemotaxis-based methodology, even when some archaea are known to have a chemotactic system. We’re expanding the scope,” explained Riekeles.

“H. volcanii thrives in extremely salty environments and can be a good model of life like we see on Mars.”

The researchers used a simplified approach. This will involve whether there is a difference between whether it is feasible in future space missions. Instead of the complex instrument, we used a slide with two chambers separated by a thin membrane. The microorganisms are placed on one side and chemical L-serine is added to the other side.

“If microorganisms are alive and can move, they can swim through the membrane towards L. serine,” explained Riekeles. “This method is simple and affordable and doesn’t require a powerful computer to analyze the results.”

However, this method requires some adjustments to the process to tackle a space mission, researchers said. There are two smaller, more robust devices that can withstand the harsh conditions of space travel, and two systems that work automatically without human intervention.

Once these difficulties are overcome, microbial movements can help detect microbes that may exist in space in the Moon Europe sea, for example Jupiter.

“This approach can make life detection cheaper and faster, and it could help you achieve more with fewer resources in the future,” concluded Riekeles. “This is an easy way to find life on future Mars missions and could be a useful addition for direct motion observation techniques.”