Improved protocol for metabolite extraction and identification of respiratory quinones in extremophilic Archaea grown on mineral materials.

We investigated the metabolome of the iron- and sulfur-oxidizing, extremely thermoacidophilic archaeon Metallosphaera sedula grown on mineral pyrite (FeS2). The extraction of organic materials from these microorganisms is a major challenge because of the tight contact and interaction between cells and mineral materials. Therefore, we applied an improved protocol to break the microbial cells and separate their organic constituents from the mineral surface, to extract lipophilic compounds through liquid–liquid extraction, and performed metabolomics analyses using MALDI-TOF MS and UHPLC-UHR-Q/TOF. Using this approach, we identified several molecules involved in central carbon metabolism and in the modified Entner-Doudoroff pathway found in Archaea, sulfur metabolism-related compounds, and molecules involved in the adaptation of M. sedula to extreme environments, such as metal tolerance and acid resistance. Furthermore, we identified molecules involved in microbial interactions, i.e., cell surface interactions through biofilm formation and cell–cell interactions through quorum sensing, which relies on messenger molecules for microbial communication. Moreover, we successfully extracted and identified different saturated thiophene-bearing quinones using software for advanced compound identification (MetaboScape). These quinones are respiratory chain electron carriers in M. sedula, with biomarker potential for life detection in extreme environmental conditions.

Reference :
Gfellner SV, Colas C, Gabant G, Groninga J, Cadene M, Milojevic T. Improved protocol for metabolite extraction and identification of respiratory quinones in extremophilic Archaea grown on mineral materials. Front Microbiol. 2025 Jan 8;15:1473270. doi: 10.3389/fmicb.2024.1473270

Radio Campus Orléans broadcast “Astrobiology, search of life on Mars”

Astrobiology investigates the origin of life, the conditions and processes that support or challenge life, and whether life exists or has ever existed elsewhere in the Universe.

In this broadcast for Radio Campus, Tetyana Milojevic talks about Mars-relevant biosignatures, antient forms of life on Earth, microbial survival outside the International Space Station and other space life science investigations at CBM.

The study of terrestrial fossils in ancient rocks: a crucial approach to identify potential signs of life on Mars

The NASA Perseverance rover is actively exploring Jezero Crater, analyzing igneous and sedimentary rocks from the crater floor and delta deposits. The rock samples that will be returned by the Mars Sample Return (MSR) mission in the 2030s will be subjected to detailed laboratory studies.

Some samples may contain traces of ancient Martian life, which are challenging to detect due to their morphological simplicity and subtle geochemical expressions. Using volcanic sediments from Kitty’s Gap Chert (Pilbara, Australia) of 3.45 billion years as analogues, researchers detail the steps needed to demonstrate their syngenicity and biogenicity. Various analytical methods, including optical and electron microscopy, Raman spectroscopy, X-ray fluorescence spectroscopy, and mass spectrometry, have been employed at different scales. Sedimentological, petrological, mineralogical, and geochemical analyses document a coastal environment of deposition, consistent with the development of microbial life. Morphological, elemental, and molecular analyses of carbonaceous matter associated with potential fossil remnants reveal enrichment in bioessential trace metals (V, Cr, Fe, Co, etc.) and colocalized aromatic and aliphatic molecules of biological origin. This study illustrates the analytical protocol necessary to optimize the detection of fossil traces of life in Martian rocks.

This work is reported on the CNRS Chimie website

Reference
Multi-Technique Characterization of 3.45 Ga Microfossils on Earth: A Key Approach to Detect Possible Traces of Life in Returned Samples from Mars
Laura Clodoré, Frédéric Foucher, Keyron Hickman-Lewis, Stéphanie Sorieul, Jean Jouve, Matthieu Réfrégiers, Guillaume Collet, Stéphane Petoud, Bernard Gratuze, Frances Westall
Astrobiology 2024
http://doi.org/10.1089/ast.2023.0089