Exposure of amino acids and derivatives in the Earth orbit

Barbier, Bernard; Hénin, Odile; Boillot, François; Chabin, Annie; Chaput, Didier; Brack, Andrè

doi:10.1016/s0032-0633(02)00010-7

Cited by 24 publications

(12 citation statements)

References 21 publications

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“…This amino acid is also used in the photosystem II of chloroplasts, acting as the electron donor of the oxidized chlorophyll. Tyrosine, because of its aromatic ring, absorbs strongly at 280 nm (Chang, 2000) and, like RNA/DNA in water, has demonstrated chemical stability under high doses of UV radiation (Barbiera et al, 2002), suggesting that its initial association with RNA/DNA may have been as a robust antenna type of photon absorber to augment the local water temperature sufficiently for denaturation.…”

Section: Evolutionmentioning

confidence: 99%

Thermodynamic dissipation theory for the origin of life

Michaelian

2011

Earth Syst. Dynam.

168

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Abstract. Understanding the thermodynamic function of life may shed light on its origin. Life, as are all irreversible processes, is contingent on entropy production. Entropy production is a measure of the rate of the tendency of Nature to explore available microstates. The most important irreversible process generating entropy in the biosphere and, thus, facilitating this exploration, is the absorption and transformation of sunlight into heat. Here we hypothesize that life began, and persists today, as a catalyst for the absorption and dissipation of sunlight on the surface of Archean seas. The resulting heat could then be efficiently harvested by other irreversible processes such as the water cycle, hurricanes, and ocean and wind currents. RNA and DNA are the most efficient of all known molecules for absorbing the intense ultraviolet light that penetrated the dense early atmosphere and are remarkably rapid in transforming this light into heat in the presence of liquid water. From this perspective, the origin and evolution of life, inseparable from water and the water cycle, can be understood as resulting from the natural thermodynamic imperative of increasing the entropy production of the Earth in its interaction with its solar environment. A mechanism is proposed for the reproduction of RNA and DNA without the need for enzymes, promoted instead through UV light dissipation and diurnal temperature cycling of the Archean sea-surface.

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Section: Evolutionmentioning

confidence: 99%

Thermodynamic dissipation theory for the origin of life

Michaelian

2011

Earth Syst. Dynam.

168

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“…Irradiation experiments were performed at room temperature (290 K) because the temperature of exposed cells in low Earth orbit was about 230-310 K (Barbier et al 1998;Barbier et al 2002;Boillot et al 2002;Guan et al 2010). Each film was irradiated with VUV light with an energy of 7.2 eV (FWHM~0.5 eV, wavelength l=172 nm) using a Xe 2 * excimer lamp (UER20H-172A, USHIO) under vacuum (pressure<10 −4 Pa) for 20, 30, 60, 240 or 600 s. The irradiation flux p was determined to be 5.4×10 15 photons cm −2 s −1 using a calibrated photodiode (S1337-1010BQ, Hamamatsu Photonics).…”

Section: Vuv Irradiationmentioning

confidence: 99%

“…The photo-stability of pure amino acids under polychromatic ultraviolet irradiation has been examined at low Earth orbit (Barbier et al 1998;Barbier et al 2002;Boillot et al 2002;Cottin et al 2008;Guan et al 2010) and in laboratories (Ehrenfreund et al 2001;ten Kate et al 2005). However, as Schwell et al (2006) have already stated, it is also important to examine the decomposition and oligomerization rates induced by monochromatic light to understand the photochemistry of extraterrestrial organic molecules.…”

Section: Introductionmentioning

confidence: 99%

Quantum Yields of Decomposition and Homo-Dimerization of Solid L-Alanine Induced by 7.2 eV Vacuum Ultraviolet Light Irradiation: An Estimate of the Half-Life of L-Alanine on the Surface of Space Objects

Izumi

Nakagawa

2011

Orig Life Evol Biosph

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One of the leading hypotheses regarding the origin of prebiotic molecules on primitive Earth is that they formed from inorganic molecules in extraterrestrial environments and were delivered by meteorites, space dust and comets. To evaluate the availability of extraterrestrial amino acids, it is necessary to examine their decomposition and oligomerization rates as induced by extraterrestrial energy sources, such as vacuum ultraviolet (VUV) and X-ray photons and high energy particles. This paper reports the quantum yields of decomposition ((8.2 ± 0.7) × 10(-2) photon(-1)) and homo-dimerization ((1.2 ± 0.3) × 10(-3) photon(-1)) and decomposition of the dimer (0.24 ± 0.06 photon(-1)) of solid L-alanine (Ala) induced by VUV light with an energy of 7.2 eV. Using these quantum yields, the half-life of L-Ala on the surface of a space object in the present earth orbit was estimated to be about 52 days, even when only photons with an energy of 7.2 eV emitted from the present Sun were considered. The actual half-life of solid L-Ala on the surface of a space object orbit around the present day Earth would certainly be much shorter than our estimate, because of the added effect of photons and particles of other energies. Thus, we propose that L-Ala needs to be shielded from solar VUV in protected environments, such as the interior of a meteorite, within a time scale of days after synthesis to ensure its arrival on the primitive Earth.

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“…We have already shown that amino acid synthesis is possible inside cometary grains under interstellar environment conditions (Munoz Caro, 2002). We are now interested in the effects of space conditions and meteoritic impact on these amino acids (Cottin, 2008;Barbier, 2002;Boillot, 2002). Most of the extraterrestrial organic molecules known today have been identified in carbonaceous chondrite meteorites (Cronin, 1993).…”

Section: Formation Of Protonated Methanimine As a Keymentioning

confidence: 99%

Special Issue: Abstracts from the Eighth European Workshop on Astrobiology, Neuchâtel, Switzerland, 1-3 September, 2008

2009

Orig Life Evol Biosph

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Exposure of amino acids and derivatives in the Earth orbit

Cited by 24 publications

References 21 publications

Thermodynamic dissipation theory for the origin of life

Thermodynamic dissipation theory for the origin of life

Quantum Yields of Decomposition and Homo-Dimerization of Solid L-Alanine Induced by 7.2 eV Vacuum Ultraviolet Light Irradiation: An Estimate of the Half-Life of L-Alanine on the Surface of Space Objects

Special Issue: Abstracts from the Eighth European Workshop on Astrobiology, Neuchâtel, Switzerland, 1-3 September, 2008

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