Investigating complex organic compounds in a simulated Mars environment

Kate, I. L. ten; Ruiterkamp, R.; Botta, Oliver; Lehmann, B.; Hernández, C.; Boudin, N.; Foing, B. H.; Ehrenfreund, P.

doi:10.1017/s1473550403001277

Cited by 11 publications

(1 citation statement)

References 52 publications

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“…In 2003, Leiden University in cooperation with the ESA conducted a series of experiments regarding habitability on Mars and tested once again the reliability of Viking's results (Ten Kate et al 2003).…”

Section: Introductionmentioning

confidence: 99%

New model of Mars surface irradiation for the climate simulation chamber ‘Artificial Mars’

Tarasashvili¹,

Sabashvili²,

Tsereteli³

et al. 2013

International Journal of Astrobiology

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A new model of the Mars surface irradiation has been developed for the imitation of radiationtemperature parameters within Mars Climate Simulation Chamber (MCSC). In order to determine the values of annual and diurnal variations of the irradiance on the Martian surface, the Solar illumination E has been expressed by the distance r between the Sun and Mars and the Sun's altitude z in the Martian sky, along with its midday zenith distance z min . The arrangements of spring and autumn equinoxes as well as summer and winter solstice points in the Martian sky are discussed regarding the perihelion of Mars. Annual orbital points and variability of Solar z min for different planetary latitudes have been calculated for the 15 selected values of Mars's true anomaly, along with the illumination E for 12 hourly moments of Martian daytime on the Martian equator. These original calculations and the data which have been obtained are used for the construction of technical tools imitating variations of the surface irradiation and temperature within MCSC, programming of the supporting computer and the electric scheme, which provide proper remote control and set the environmental parameters that are analogues to the 24 hours 39 minutes circadian cycle on planet Mars. Spectral distribution as monochromatic irradiance, humidity control, atmospheric composition and other environmental parameters of planet Mars are also imitated and remotely controlled within MCSC, however, are not discussed in this particular article.

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Section: Introductionmentioning

confidence: 99%

New model of Mars surface irradiation for the climate simulation chamber ‘Artificial Mars’

Tarasashvili¹,

Sabashvili²,

Tsereteli³

et al. 2013

International Journal of Astrobiology

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Photooxidation of Nucleic Acids on Metal Oxides: Physicochemical and Astrobiological Perspectives

et al. 2011

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Photocatalytic oxidation of nucleic acid components on aqueous metal oxides (TiO2, α-FeOOH, and α-Fe2O3) has been studied. The oxidation of purine nucleotides results in the formation of the purine radical cations and sugar-phosphate radicals, whereas the oxidation of pyrimidine nucleotides other than thymine results in the oxidation of only the sugar-phosphate. The oxidation of the thymine (and to a far less extent for the 5-methylcytosine) derivatives results in deprotonation from the methyl group of the base. Some single stranded (ss) oligoribonucleotides and wild-type ss RNA were oxidized at purine sites. In contrast, double stranded (ds) oligoribonucleotides and DNA were not oxidized. These results account for observations suggesting that cellular ds DNA is not damaged by exposure to photoirradiated TiO2 nanoparticles inserted into the cell, whereas ss RNA is extensively damaged. The astrobiological import of our observations is that the rapid degradation of monomer nucleotides make them poor targets as biosignatures, whereas duplex DNA is a better target as it is resilient to oxidative diagenesis. Another import of our studies is that ds DNA (as opposed to ss RNA) appears to be optimized to withstand oxidative stress both due to the advantageous polymer morphology and the subtle details of its radical chemistry. This peculiarity may account for the preference for DNA over RNA as a “molecule of life” provided that metal oxides served as the template for synthesis of polynucleotides, as suggested by Orgel and others.

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Light Induced Fragmentation of Polyfunctional Carboxylated Compounds on Hydrated Metal Oxide Particles: From Simple Organic Acids to Peptides

Shkrob

Chemerisov

2009

J. Phys. Chem. C

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Light induced reactions of carboxylic, hydroxycarboxylic, and aminocarboxylic acids, carboxylated aromatics, and α-amino acids and peptides adsorbed on hydrated anatase (TiO2), goethite (α-FeOOH), and hematite (α-Fe2O3) have been studied at low temperature (77−200 K), by means of electron paramagnetic resonance (EPR) spectroscopy, and at 295 K, by means of transient absorption spectroscopy. In the room-temperature solution, the photocatalytic decomposition of carboxylated molecules, in the absence of synergistic adsorption by hydroxyl groups (e.g., in serine), is inefficient due to weak surface binding. The yield of radical formation increases significantly at low temperature, as the carboxylated molecules adsorb on the surface. The main photodegradation path is decarboxylation initiated by charge transfer from the metal oxide to the adsorbate. Below 120 K, for carboxylic acids and nonaromatic amino acids and peptides, the decarboxylation is the only reaction pathway, yielding the corresponding C-centered radicals. At higher temperature these radicals become mobile and abstract H from the parent molecules. For aromatic amino acids (histidine, tyrosine, and tryptophan) charge transfer followed by deprotonation is the predominant photoreaction. For polycarboxylated aromatics, the outcome of the charge transfer is determined by the stability of the trapped-hole species. In addition to trapping holes, some adsorbates, such as mellitic acid, trap surface electrons. The photocatalytic activity of the anatase, goethite, and hematite are similar for aromatic, carboxylic, and hydroxycarboxylic acids; for hematite, this activity reduces markedly for α-amino acids and peptides. The rutile is inactive toward these carboxylated molecules. These findings are related to martian soil chemistry, biomedical chemistry, and photocatalysis.

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Investigating complex organic compounds in a simulated Mars environment

Cited by 11 publications

References 52 publications

New model of Mars surface irradiation for the climate simulation chamber ‘Artificial Mars’

New model of Mars surface irradiation for the climate simulation chamber ‘Artificial Mars’

Photooxidation of Nucleic Acids on Metal Oxides: Physicochemical and Astrobiological Perspectives

Light Induced Fragmentation of Polyfunctional Carboxylated Compounds on Hydrated Metal Oxide Particles: From Simple Organic Acids to Peptides

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