Ionic Strength Is a Barrier to the Habitability of Mars

Fox-Powell, Mark; Hallsworth, John E.; Cousins, C. R.; Cockell, Charles S.

doi:10.1089/ast.2015.1432

Cited by 115 publications

(129 citation statements)

References 74 publications

(30 reference statements)

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“…Perchlorates, as hydroscopic substances, bind water from the atmosphere and contribute to the formation of these brines, which remain liquid at low temperatures prevailing on the surface of Mars (Gough et al, 2011; Toner and Catling, 2016). Martian brines contain high amounts of different dissolved salts, including chlorides, sulfates, and perchlorates (Kounaves et al, 2014; Fox-Powell et al, 2016). Within this transient liquid water on the surface of Mars, a simultaneous appearance of high salt concentrations and perchlorates occur (Martín-Torres et al, 2015).…”

Section: Discussionmentioning

confidence: 99%

High Tolerance of Hydrogenothermus marinus to Sodium Perchlorate

2017

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On Mars, significant amounts (0.4–0.6%) of perchlorate ions were detected in dry soil by the Phoenix Wet Chemistry Laboratory and later confirmed with the Mars Science Laboratory. Therefore, the ability of Hydrogenothermus marinus, a desiccation tolerant bacterium, to survive and grow in the presence of perchlorates was determined. Results indicated that H. marinus was able to tolerate concentrations of sodium perchlorate up to 200 mM ( 1.6%) during cultivation without any changes in its growth pattern. After the addition of up to 440 mM ( 3.7%) sodium perchlorate, H. marinus showed significant changes in cell morphology; from single motile short rods to long cell chains up to 80 cells. Furthermore, it was shown that the known desiccation tolerance of H. marinus is highly influenced by a pre-treatment with different perchlorates; additive effects of desiccation and perchlorate treatments are visible in a reduced survival rate. These data demonstrate that thermophiles, especially H. marinus, have so far, unknown high tolerances against cell damaging treatments and may serve as model organisms for future space experiments.

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Section: Discussionmentioning

confidence: 99%

High Tolerance of Hydrogenothermus marinus to Sodium Perchlorate

2017

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“…A limited number of studies have also sought to determine how combinations of multiple extremes influence physical and chemical boundaries for microbial multiplication and survival [2][3][4][5]10,12,13]. One application of this research is to understand how complex interactions between environmental extremes affect microbial susceptibility to antibiotic compounds and, conversely, how these compounds may alter the responses of organisms to extreme conditions.…”

Section: Resultsmentioning

confidence: 99%

Astrobiology as a framework for investigating antibiotic susceptibility: a study ofHalomonas hydrothermalis

Harrison

Angel

Cockell

2017

J. R. Soc. Interface.

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Physical and chemical boundaries for microbial multiplication on Earth are strongly influenced by interactions between environmental extremes. However, little is known about how interactions between multiple stress parameters affect the sensitivity of microorganisms to antibiotics. Here, we assessed how 12 distinct permutations of salinity, availability of an essential nutrient (iron) and atmospheric composition (aerobic or microaerobic) affect the susceptibility of a polyextremotolerant bacterium, Halomonas hydrothermalis, to ampicillin, kanamycin and ofloxacin. While salinity had a significant impact on sensitivity to all three antibiotics (as shown by turbidimetric analyses), the nature of this impact was modified by iron availability and the ambient gas composition, with differing effects observed for each compound. These two parameters were found to be of particular importance when considered in combination and, in the case of ampicillin, had a stronger combined influence on antibiotic tolerance than salinity. Our data show how investigating microbial responses to multiple extremes, which are more representative of natural habitats than single extremes, can improve our understanding of the effects of antimicrobial compounds and suggest how studies of habitability, motivated by the desire to map the limits of life, can be used to systematically assess the effectiveness of antibiotics.

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“…This discrepancy can originate from the non-additive effects of salts and organic molecules in inducing a net kosmotropic or chaotropic effect. For instance, simulated martian brine solutions are predominantly kosmotropic despite being constituted with chaotropic salts such as chlorides of iron and magnesium [70].…”

Section: On Kosmotropes and Chaotropesmentioning

confidence: 99%

“…For instance, simulated martian brine solutions are predominantly kosmotropic despite being constituted with chaotropic salts such as chlorides of iron and magnesium [70]. activities of guanidine, urea, mannitol, sorbitol, trehalose, glycine, betaine, and ectoine as determined by systematic studies on agar gelation [69].…”

Section: On Kosmotropes and Chaotropesmentioning

confidence: 99%

Modulating Nucleation by Kosmotropes and Chaotropes: Testing the Waters

2017

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Abstract:Water is a fundamental solvent sustaining life, key to the conformations and equilibria associated with solute species. Emerging studies on nucleation and crystallization phenomena reveal that the dynamics of hydration associated with mineral precursors are critical in determining material formation and growth. With certain small molecules affecting the hydration and conformational stability of co-solutes, this study systematically explores the effects of these chaotropes and kosmotropes as well as certain sugar enantiomers on the early stages of calcium carbonate formation. These small molecules appear to modulate mineral nucleation in a class-dependent manner. The observed effects are finite in comparison to the established, strong interactions between charged polymers and intermediate mineral forms. Thus, perturbations to hydration dynamics of ion clusters by co-solute species can affect nucleation phenomena in a discernable manner.

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Ionic Strength Is a Barrier to the Habitability of Mars

Abstract: Habitability-Mars-Salts-Water activity-Life in extreme environments. Astrobiology 16, 427-442.

Cited by 115 publications

References 74 publications

High Tolerance of Hydrogenothermus marinus to Sodium Perchlorate

High Tolerance of Hydrogenothermus marinus to Sodium Perchlorate

Astrobiology as a framework for investigating antibiotic susceptibility: a study ofHalomonas hydrothermalis

Modulating Nucleation by Kosmotropes and Chaotropes: Testing the Waters

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