Beyond Chloride Brines: Variable Metabolomic Responses in the Anaerobic Organism Yersinia intermedia MASE-LG-1 to NaCl and MgSO4 at Identical Water Activity

Abstract

Growth in sodium chloride (NaCl) is known to induce stress in non-halophilic microorganisms leading to effects on the microbial metabolism and cell structure. Microorganisms have evolved a number of adaptations, both structural and metabolic, to counteract osmotic stress. These strategies are well-understood for organisms in NaCl-rich brines such as the accumulation of certain organic solutes (known as either compatible solutes or osmolytes). Less well studied are responses to ionic environments such as sulfate-rich brines which are prevalent on Earth but can also be found on Mars. In this paper, we investigated the global metabolic response of the anaerobic bacterium Yersinia intermedia MASE-LG-1 to osmotic salt stress induced by either magnesium sulfate (MgSO4) or NaCl at the same water activity (0.975). Using a non-targeted mass spectrometry approach, the intensity of hundreds of metabolites was measured. The compatible solutes L-asparagine and sucrose were found to be increased in both MgSO4 and NaCl compared to the control sample, suggesting a similar osmotic response to different ionic environments. We were able to demonstrate that Yersinia intermedia MASE-LG-1 accumulated a range of other compatible solutes. However, we also found the global metabolic responses, especially with regard to amino acid metabolism and carbohydrate metabolism, to be salt-specific, thus, suggesting ion-specific regulation of specific metabolic pathways.

Asparagine and nitric oxide jointly enhance antioxidant capacity and nitrogen metabolism to improve drought resistance in cotton: Evidence from long‐term field trials

“…It is likely that Asn and NO interact with each other and the plant in certain ways that increase the plant's tolerance to drought, which might account for the synergistic action of these two compounds in enhancing the water relations of cotton plants during drought stress. Asn is well‐known to play a role in osmoregulation and to support the maintenance of cellular turgor under drought stress (Schwendner et al, 2018; Yadav et al, 2019), whereas NO has been demonstrated to protect plants from oxidative stress, enhance the activity of antioxidant enzymes, and modulate the expression of genes related to the stress response (Cao et al, 2019). When applied together, Asn and SNP may act to complement each other's effects, leading to a greater improvement in the plant's water relations and tolerance to drought stress compared to either compound alone.…”

Taxonomic and functional analyses of intact microbial communities thriving in extreme, astrobiology-relevant, anoxic sites

“…It is our intention to exploit those model organisms and to analyze their physiological properties to understand their resistances to, e.g. radiation and to estimate, whether they could survive extraterrestrial conditions (see also [ 75 – 78 ]). Information on a diverse set of (anaerobic) taxa, which were present in all sampling sites could be retrieved, and also several signatures of known taxa with astrobiological relevance were detected [ 23 , 79 – 82 ].…”

“…Our study has contributed novel insights into the microbiology of analogue sites. In particular, a number of highly valuable model organisms has been retrieved, which directly feeds into the other goals of the MASE project, namely studying the limits of growth of selected isolates, deciphering the molecular principles of resistances [ 78 ], analysing the genomic and metabolomic inventory of representative microbes [ 75 ], studying the fossilization processes and detectability of biomarkers during artificial fossilization [ 85 ] and the optimization of automated life detection [ 1 , 86 ]. However, numerous tasks remain to be accomplished in future.…”

Lack of correlation of desiccation and radiation tolerance in microorganisms from diverse extreme environments tested under anoxic conditions

“…Recently, it has been reported that the response of Y. intermedia MASE-LG-1 to salt stress (e.g. NaCl) involves an accumulation of L-asparagine and sucrose which might be one explanation for its tolerance to desiccation (Schwendner et al 2017 ). For Halanaerobium praevalens , a close relative to the MASE strain Halanaerobium sp.…”