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1.
Talanta ; 179: 238-245, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29310228

RESUMO

The present work aims at developing two LC-HRMS setups for the screening of organic matter in astrophysical samples. Their analytical development has been demonstrated on a 100-µg residue coming from the photo-thermo chemical processing of a cometary ice analog produced in laboratory. The first 1D-LC-HRMS setup combines a serially coupled columns configuration with HRMS detection. It has allowed to discriminate among different chemical families (amino acids, sugars, nucleobases and oligopeptides) in only one chromatographic run without neither a priori acid hydrolysis nor chemical derivatisation. The second setup is a dual-LC configuration which connects a series of trapping columns with analytical reverse-phase columns. By coupling on-line these two distinct LC units with a HRMS detection, high mass compounds (350

2.
Science ; 355(6321): 141, 2017 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-28082555

RESUMO

We detected ribose and related sugars in the organic residues of simulated interstellar ices using multidimensional gas chromatography. Kawai questions the formation of sugar compounds in the ices and suggests that they arise from a classical formose reaction during sample workup for analysis. We disagree with this hypothesis and present additional data to argue that Kawai's criticism does not apply.


Assuntos
Gelo/análise , Ribose , Meio Ambiente Extraterreno , Compostos Orgânicos , Raios Ultravioleta
3.
Science ; 352(6282): 208-12, 2016 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-27124456

RESUMO

Ribose is the central molecular subunit in RNA, but the prebiotic origin of ribose remains unknown. We observed the formation of substantial quantities of ribose and a diversity of structurally related sugar molecules such as arabinose, xylose, and lyxose in the room-temperature organic residues of photo-processed interstellar ice analogs initially composed of H2O, CH3OH, and NH3 Our results suggest that the generation of numerous sugar molecules, including the aldopentose ribose, may be possible from photochemical and thermal treatment of cosmic ices in the late stages of the solar nebula. Our detection of ribose provides plausible insights into the chemical processes that could lead to formation of biologically relevant molecules in suitable planetary environments.


Assuntos
Radiação Cósmica , Gelo , Origem da Vida , RNA/química , Ribose/síntese química , Ácido Acético/química , Amônia/química , Arabinose/síntese química , Meio Ambiente Extraterreno , Meteoroides , Pentoses/síntese química , Processos Fotoquímicos , Raios Ultravioleta , Xilose/síntese química
4.
Proc Natl Acad Sci U S A ; 112(4): 965-70, 2015 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-25583475

RESUMO

Evolved interstellar ices observed in dense protostellar molecular clouds may arguably be considered as part of precometary materials that will later fall on primitive telluric planets, bringing a wealth of complex organic compounds. In our laboratory, experiments reproducing the photo/thermochemical evolution of these ices are routinely performed. Following previous amino acid identifications in the resulting room temperature organic residues, we have searched for a different family of molecules of potential prebiotic interest. Using multidimensional gas chromatography coupled to time-of-flight mass spectrometry, we have detected 10 aldehydes, including the sugar-related glycolaldehyde and glyceraldehyde--two species considered as key prebiotic intermediates in the first steps toward the synthesis of ribonucleotides in a planetary environment. The presence of ammonia in water and methanol ice mixtures appears essential for the recovery of these aldehydes in the refractory organic residue at room temperature, although these products are free of nitrogen. We finally point out the importance of detecting aldehydes and sugars in extraterrestrial environments, in the gas phase of hot molecular clouds, and, more importantly, in comets and in primitive meteorites that have most probably seeded the Earth with organic material as early as 4.2 billion years ago.

5.
Phys Life Rev ; 8(3): 307-30, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21924690

RESUMO

Proteins of all living organisms including plants, animals, and humans are made up of amino acid monomers that show identical stereochemical L-configuration. Hypotheses for the origin of this symmetry breaking in biomolecules include the absolute asymmetric photochemistry model by which interstellar ultraviolet (UV) circularly polarized light (CPL) induces an enantiomeric excess in chiral organic molecules in the interstellar/circumstellar media. This scenario is supported by a) the detection of amino acids in the organic residues of UV-photo-processed interstellar ice analogues, b) the occurrence of L-enantiomer-enriched amino acids in carbonaceous meteorites, and c) the observation of CPL of the same helicity over large distance scales in the massive star-forming region of Orion. These topics are of high importance in topical biophysical research and will be discussed in this review. Further evidence that amino acids and other molecules of prebiotic interest are asymmetrically formed in space comes from studies on the enantioselective photolysis of amino acids by UV-CPL. Also, experiments have been performed on the absolute asymmetric photochemical synthesis of enantiomer-enriched amino acids from mixtures of astrophysically relevant achiral precursor molecules using UV-circularly polarized photons. Both approaches are based on circular dichroic transitions of amino acids that will be highlighted here as well. These results have strong implications on our current understanding of how life's precursor molecules were possibly built and how life selected the left-handed form of proteinogenic amino acids.


Assuntos
Aminoácidos/efeitos da radiação , Exobiologia , Meio Ambiente Extraterreno/química , Processos Fotoquímicos , Aminoácidos/química , Aminoácidos/metabolismo , Animais , Humanos , Modelos Biológicos , Estereoisomerismo
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