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Raggi, L, Bada JL, Lazcano A.  2016.  On the lack of evolutionary continuity between prebiotic peptides and extant enzymes. Physical Chemistry Chemical Physics. 18:20028-20032.   10.1039/c6cp00793g   AbstractWebsite

The significance of experiments that claim to simulate the properties of prebiotic small peptides and polypeptides as models of the polymers that may have preceded proteins is critically addressed. As discussed here, most of these experiments are based only on a small number of a larger set of amino acids that may have been present in the prebiotic environment, supported by both experimental simulations and the repertoire of organic compounds reported in carbonaceous chondrites. Model experiments with small peptides may offer some insights into the processes that contributed to generate the chemical environment leading to the emergence of informational oligomers, but not to the origin of proteins. The large body of circumstantial evidence indicating that catalytic RNA played a key role in the origin of protein synthesis during the early stages of cellular evolution implies that the emergence of the genetic code and of protein biosynthesis are no longer synonymous with the origin of life. Hence, reports on the abiotic synthesis of small catalytic peptides under potential prebiotic conditions do not provide information on the origin of triplet encoded protein biosynthesis, but in some cases may serve as models to understand the properties of the earliest proteins.

Bada, JL, Cronin JR, Ho MS, Kvenvolden KA, Lawless JG, Miller SL, Oro J, Steinberg S.  1983.  On the Reported Optical-Activity of Amino-Acids in the Murchison Meteorite. Nature. 301:494-496.   10.1038/301494a0   Website
Skelley, AM, Aubrey AD, Willis PA, Amashukeli X, Ehrenfreund P, Bada JL, Grunthaner FJ, Mathies RA.  2007.  Organic amine biomarker detection in the Yungay region of the Atacama Desert with the Urey instrument. Journal of Geophysical Research-Biogeosciences. 112   10.1029/2006jg000329   AbstractWebsite

The Urey in situ organic compound analysis instrument, consisting of a subcritical water extractor ( SCWE) and a portable microchip capillary electrophoresis instrument called the Mars Organic Analyzer ( MOA), was field tested in the Atacama Desert, Chile, in June 2005. Soil samples from the most arid Yungay region were collected, biomarkers were extracted by the SCWE, and organic amine composition and amino acid chirality analysis was performed by the MOA. Samples collected from the top 1 cm of duracrust soil but shielded from the ambient environment by rocks were compared to the exposed duracrust. The shielded duracrust yielded amines and amino acids ranging from 50 to 100 ppb, while amino acid signals from the exposed duracrust were below blank levels. Samples from buried gypsum deposits located directly above a water flow channel contained amino acids ranging from 13 to 90 ppb. Chiral analysis revealed D/L ratios of 0.39 +/- 0.08 and 0.34 +/- 0.07 for alanine/serine and 0.78 +/- 0.06 for aspartic acid, indicating significant racemization of biologically produced amino acids. On the basis of the D/L ratios, we estimate sample ages ranging from 10(3) to 10(5) years. These results demonstrate the successful field testing of the Urey instrument, as well as the detection of biomarkers from past terrestrial life in one of the most arid and Mars-like regions on Earth.

Zenobi, R, Philippoz JM, Zare RN, Wing MR, Bada JL, Marti K.  1992.  Organic-Compounds in the Forest Vale, H4 Ordinary Chondrite. Geochimica Et Cosmochimica Acta. 56:2899-2905.   10.1016/0016-7037(92)90366-q   AbstractWebsite

We have analyzed the H4 ordinary chondrite Forest Vale for polycyclic aromatic hydrocarbons (PAHs) using two-step laser mass spectrometry (L2MS) and for amino acids using a standard chromatographic method. Indigenous PAHs were identified in the matrices of freshly cleaved interior faces but could not be detected in pulverized silicates and chondrules. No depth dependence of the PAHs was found in a chipped interior piece. Amino acids, taken from the entire sample, consisted of protein amino acids that were nonracemic, indicating that they are terrestrial contaminants. The presence of indigenous PAHs and absence of indigenous amino acids provides support for the contention that different processes and environments contributed to the synthesis of the organic matter in the solar system.

Arrhenius, G, Bada JL, Joyce GF, Lazcano A, Miller S, Orgel LE.  1999.  Origin and ancestor: Separate environments. Science. 283:792-792.Website
Bada, JL, Lazcano A.  2002.  Origin of life - Some like it hot, but not the first biomolecules. Science. 296:1982-1983.   10.1126/science.1069487   Website
Becker, L, Popp B, Rust T, Bada JL.  1999.  The origin of organic matter in the Martian meteorite ALH84001. Earth and Planetary Science Letters. 167:71-79.   10.1016/s0012-821x(99)00014-x   AbstractWebsite

Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta(13)C values for the organic matter associated with the carbonate globules averaged -26 parts per thousand and is attributed to terrestrial contamination, In contrast, the delta(13)C values for the organic matter associated with the bulk matrix material yielded a value of -15 parts per thousand. The only common sources of carbon on the Earth that yield similar delta(13)C values, other then some diagenetically altered marine carbonates, are C(4) plants. A delta(13)C value of -15 parts per thousand, on the other hand, is consistent with a kerogen-like component, the most ubiquitous form of organic matter found in carbonaceous chondrites such as the Murchison meteorite. Examination of the carbonate globules and bulk matrix material using laser desorption mass spectrometry (LDMS) indicates the presence of a high molecular weight organic component which appears to be extraterrestrial in origin, possibly derived from the exogenous delivery of meteoritic or cometary debris to the surface of Mars. (C) 1999 Published by Elsevier Science B.V. All rights reserved.

Becker, L, Popp B, Rust T, Bada JL.  1999.  The origin of organic matter in the Martian meteorite ALH84001. Life Sciences: New Insights into Complex Organics in Space. 24( Ehrenfreund P, Robert F, Eds.).:477-488., Oxford: Pergamon Press Ltd   10.1016/s0273-1177(99)00090-3   Abstract

Stable carbon isotope measurements of the organic matter associated with the carbonate globules and the bulk matrix material in the ALH84001 Martian meteorite indicate that two distinct sources are present in the sample. The delta(13) C values for the organic matter associated with the carbonate globules averaged -26 parts per thousand and is attributed to terrestrial contamination. In contrast, the delta(13)C values for the organic matter associated with the bulk matrix material yielded a value of -15 parts per thousand. The only common carbon sources on the Earth that yield similar delta(13) values, other then some diagenetically altered marine carbonates, are C(4) plants. A delta(13)C value of -15 parts per thousand, on the other hand, is consistent with a kerogen-like component, the most ubiquitous form of organic matter found in carbonaceous chondrites such as the Murchison meteorite. Examination of the carbonate globules and bull; matrix material using laser desorption mass spectrometry (LDMS) indicates the presence of a high molecular weight organic component which appears to be extraterrestrial in origin, possibly derived from the exogenous delivery of meteoritic or cometary debris to the surface of Mars. (C) 1999 COSPAR. Published by Elsevier Science Ltd.

Wing, MR, Bada JL.  1992.  The Origin of the Polycyclic Aromatic-Hydrocarbons in Meteorites. Origins of Life and Evolution of the Biosphere. 21:375-383. AbstractWebsite

Polycyclic aromatic hydrocarbons (PAHs) in Cl and C2 Carbonaceous Chondrites appear to be the product of a high-temperature synthesis. This observation counters a prevailing view that PAHs in meteorites are a thermal alternation product of preexisting aliphatic compounds, which in turn required the presence of low-temperature mineral phases such as magnetite and hydrated phyllosilicates for their formation. Such a process would necessarily lead to a more low-temperature assemblage of PAHs, as many low-temperature minerals and compounds are extant in meteorites. Ivuna, a C1 carbonaceous chondrite, has been shown to contain abundant amounts of the three-ring PAHs phenanthrene/anthracene, but no detectable levels of the two- and four-ring PAHs naphthalene and pyrene/fluoranthene. Ivuna and other C1 carbonaceous chondrites are known to have been extensively altered by water. The aqueous solubilities of PAHs indicate that some PAHs would have been mobilized during the aqueous alteration phase in meteorite parent bodies. Model geochromatography experiments using crushed serpentine or beach sand as the solid phase and water for elution suggest that the complete separation of two, three, and four-ring PAHs could be expected to occur in the parent body of C1 carbonaceous chondrites. It is proposed that aqueous fluids driven by heat in the parent body of Ivuna migrated from the interior to the surface, in the process transporting, separating and concentrating PAHs at various zones in the parent body. The presence of indigenous PAHs and absence of indigenous amino acids in the H4 ordinary chondrite Forest Vale provides support for the contention that different processes and environments contributed to the synthesis of the organic matter in the solar system.

Bada, J.  2003.  Origins of life. Oceanography. 16:98-104.
Steinberg, SM, Bada JL.  1984.  Oxalic, Glyoxalic and Pyruvic Acids in Eastern Pacific-Ocean Waters. Journal of Marine Research. 42:697-708.Website