Abstract EANA2024-17

Despite being called "The Final Frontier," the majority of the universe's conditions are too unsafe for life to survive. The only known life capable of living in extreme settings are the life of extremophiles. They can live in conditions with high levels of salt (halophiles) or high or low temperatures (thermophiles or psychrophiles), acid or alkaline environments (acidophiles or alkaliphiles), dry conditions (xerophiles) and high levels of radiation (radio-resistant). To grasp true boundaries of habitability is to investigate polyextremophiles that can survive in polyextreme conditions. Polyextremophiles are model microorganisms of extra-terrestrial planets and offers crucial insights on the mission to find life on other moons and planets, including Mars. The contemporary Mars polyextreme analogues site includes super-arid regions, sand dunes, hot springs, hypersaline lake and permafrost. These environments provide opportunity to isolate and study microbiology of the niche. In our study, we collected soil sample from the lakebed of Tso kar hypersaline lake situated in high-altitude region of Ladakh in India, a Mars analog site and have done the metagenomics analysis of the soil sample via DNA extraction, PCR amplification with V3-V4 Primers, sequencing using Illumina MiSeq Platform and data analysis. We then enumerated and isolated bacteria on nutrient agar media with 6% NaCl using serial dilution followed by spread plate and screen for extremophiles by streaking them under different extreme conditions [high salt concentration (10% NaCl), temperature (7 ℃ & 37 ℃), pH and in combination]. Strains showing best growth response in more than one extreme condition are considered as polyextremophiles and are identified with 16S rDNA gene sequencing. These polyextremophiles are also subjected to lipidomics analysis using an ultra-high-performance liquid chromatographic system followed by high-resolution orbitrap mass spectrometry (HRMS). Statistical analysis is done using an online server Metaboanalyst 4.0. Results shows that isoprenoids and hopanoids classes of lipids offers the potential candidate as lipid biosignature.

Keywords: Mars analogue, Ladakh, extremophiles, polyextremophiles, metagenomics, lipidomics, lipid biosignature