Summary of metagenomic sequences and assemblies for eastern South Pacific picoeukaryote samples T142 and T149.

<p>Summary of metagenomic sequences and assemblies for eastern South Pacific picoeukaryote samples T142 and T149.</p

Similarity between <i>B. prasinos</i> RCC1105 genome and T142 and T149 assemblies for the three larger chromosomes.

<p>Only regions with coverage in excess 10× for both samples were considered. Total genome and non-CDS regions were analyzed separately (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039648#s4" target="_blank">Material and Methods</a> for details).</p

GC content and coverage depth by reads from the eastern South Pacific picoeukaryote samples T142 and T149 of individual chromosomes of <i>B. prasinos</i> RCC1105.

<p>(A) Chromosome 1. (B) Chromosome 14.</p

Assignment of reads from samples T142 and T149 to individual chromosomes of <i>B. prasinos</i> RCC1105 using Geneious Assembler (see Materials and Methods for details).

<p>The numeration of chromosomes is provided both for the draft version of the genome (used in this work) and for the final version of the genome <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039648#pone.0039648-Moreau1" target="_blank">[37]</a>.</p

Table1.docx

<p>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.</p

Influence of perchlorates.

<p>Influence of perchlorates on tolerance to desiccation (A) and ionizing radiation (B). N₀: Viable cells without desiccation / irradiation, N: Viable cells after desiccation / irradiation. Recovery was performed under standard cultivation conditions without perchlorate (n = 3). Asterisks denote significant difference (<i>p</i> < 0.05) to the control (survival after desiccation without perchlorates). (A) Black columns: Cells were exposed (15 min) to 0.5% perchlorate (0.5% NaClO₄ = 35.6 mM; 0.5% Ca(Cl₄)₂ = 20.9 mM; 0.5% Mg(ClO₄)₂ = 22.4 mM) before desiccation treatment (24 h, anoxic conditions). Grey columns: Cells were exposed (15 min) to 1.0% perchlorate (1.0% NaClO₄ = 71.2 mM; 1.0% Ca(Cl₄)₂ = 41.9 mM; 1.0% Mg(ClO₄)₂ = 44.8 mM) before desiccation treatment (24 h, anoxic conditions). (B) Cells were exposed (15 min) to the indicated perchlorates before treatment with ionizing radiation up to 800 Gy. Black circles: 0.5% Mg(ClO₄)₂; White circle: 1% Mg(ClO₄)₂; Black triangle: 0.5% Na(ClO₄); White triangle: 1% Na(ClO₄); Black square 0.5% Ca(ClO₄)₂; White square: 1% Ca(ClO₄)₂.</p

Overview of performed single and combined stress tests with strain MASE-LG-1.

<p>Overview of performed single and combined stress tests with strain MASE-LG-1.</p