He Atacama desertwhich is located in the northern region Chileis one of the driest places on planet Earth. His climate creates the conditions they create it rains they are almost non-existent, which is why they are natural laboratory to investigate how life can persist in extreme situations.
In this extremely arid ecosystem there is a microbiome which includes everything from viable and active microorganisms to extracellular DNA dead or decaying microorganisms.
Scientists from Germany, Chile, United States of America y United Kingdom developed a a new technique to study better. Until now, conventional methods have been unable to distinguish DNA from living and dead microorganisms, limiting data interpretation.
The researchers published details of the use of their innovation in the journal Applied and environmental microbiology, from American Society for Microbiology. This technique allows you to separate Intracellular DNA (DNAi)typical of living cells, extracellular DNA (eDNA)originating from dead organisms.
He led the work Dirk Wagner from German Research Center for Geosciences. It had cooperation Pedro Zamoranofrom the Laboratory of Extremophilic Microorganisms of the Czech Republic University of Antofagasta in Chile. In the desert microbiome, They identified a total of 5965 bacteria.
They believed that this technique would improve the resolution of microbiological investigations in environments such as the Atacama Desert and open opportunities for conducting similar studies in extreme ecosystems.
The scientists collected soil samples at various locations, including places such as Yungayrecognized for his hyperaridand areas of higher relative humidity near the coast Pacific Ocean.
Each sample was processed using a new DNA separation method. The researchers then used high-throughput genetic sequencing techniques to identify and classify the microorganisms present.
This approach was complemented by chemical analyzes of the soil and allowed the microbial communities to relate to the specific environmental conditions of each site, such as salinity, moisture and ultraviolet radiation levels.
The analysis revealed that living microorganisms adapt to extreme conditions through specialized strategies. They were found in all samples Actinobacteria y Proteobacteriawhich are two key groups in processes such as nitrogen fixation and initial soil formation.
In the surface layers of bacteria Chloroflexi They predominated in DNAi, while in deeper areas different microbial communities influenced by water and nutrient availability were observed.
An important finding was the presence of “generalist” microorganisms that are able to tolerate a wide range of environmental conditions. There were also “specialist” microorganisms that are adapted to specific niches, such as highly saline or high sulfate soils.
This differentiation reflects the functional diversity and ability of microbes to colonize even the most inhospitable environments.
The DNA separation technique can be applied in other extreme ecosystems, such as volcanic soils or polar environments, as it facilitates the study of active microbial communities in places with extremely low biomass.
Furthermore, this approach could be key astrobiological researchbecause the Atacama desert has an environment very similar to that of the planet mars considering its climatic and geological conditions.
For example, previous research has studied salt deposits such as chlorates and perchlorate, which have also been detected in Martian soil, particularly through analyzes by robotic vehicles. Curiosity y Perseverance. These salts are of particular interest because they can affect moisture retention and biological processes.
“Microbes are the pioneers that colonize this type of environment and set the stage for the succession of life,” said Wagner, who was funded European Research Council (known as the ERC) to conduct research.
These processes, he added, are not limited to the desert: “This could also apply to the new terrain that is then created earthquake O landslideswhere there is a similar situation, a substrate based on minerals or rocks.”
FROM Chileprofessor and scientist Andrés Marcolet Calderafrom the Department of Biology, Faculty of Science, MU University of Chilehe commented Infobae about the published study: “The soil of the Atacama Desert is recognized as one of the most extreme terrestrial environments on the planet, due to its very high dryness and the presence of heavy metals.”
There have been previous studies that have already investigated the microorganisms that live there using techniques based on studying the DNA present in the soil.
“This new work – mentioned Marcoleta Caldera, who was not involved in the work – is different in that the DNA that would be inside the microbial cells is separated from the one outside, and therefore would come from bacteria that released their DNA. to the ground.”
In this way, “the idea is to distinguish between viable members of the microbial community and those that are dead.” and they would leave their DNA on the ground “some time ago,” he said.
