Publications

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A
Ambler, RP, Macko SA, Sykes B, Griffiths JB, Bada J, Eglinton G.  1999.  Documenting the diet in ancient human populations through stable isotope analysis of hair - Discussion. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences. 354:75-76.Website
Ambler, RP, Bada JL, Finch P, Grocke DR, Eglinton G, Macko SA.  1999.  Preservation of key biomolecules in the fossil record: current knowledge and future challenges - Discussion. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences. 354:86-87.Website
Arrhenius, G, Bada JL, Joyce GF, Lazcano A, Miller S, Orgel LE.  1999.  Origin and ancestor: Separate environments. Science. 283:792-792.Website
Aubrey, A, Cleaves HJ, Chalmers JH, Skelley AM, Mathies RA, Grunthaner FJ, Ehrenfreund P, Bada JL.  2006.  Sulfate minerals and organic compounds on Mars. Geology. 34:357-360.   10.1130/g22316.1   AbstractWebsite

Strong evidence for evaporitic sulfate minerals such as gypsum and jarosite has recently been found on Mars. Although organic molecules are often codeposited with terrestrial evaporitic minerals, there have been no systematic investigations of organic components in sulfate minerals. We report here the detection of organic material, including amino acids and their amine degradation products, in ancient terrestrial sulfate minerals. Amino acids and amines appear to be preserved for geologically long periods in sulfate mineral matrices. This suggests that sulfate minerals should be prime targets in the search for organic compounds, including those of biological origin, on Mars.

Aubrey, AD, Chalmers JH, Bada JL, Grunthaner FJ, Amashukeli X, Willis P, Skelley AM, Mathies RA, Quinn RC, Zent AP, Ehrenfreund P, Amundson R, Glavin DP, Botta O, Barron L, Blaney DL, Clark BC, Coleman M, Hofmann BA, Josset JL, Rettberg P, Ride S, Robert F, Sephton MA, Yen A.  2008.  The Urey instrument: An advanced in situ organic and oxidant detector for Mars exploration. Astrobiology. 8:583-595.   10.1089/ast.2007.0169   AbstractWebsite

The Urey organic and oxidant detector consists of a suite of instruments designed to search for several classes of organic molecules in the martian regolith and ascertain whether these compounds were produced by biotic or abiotic processes using chirality measurements. These experiments will also determine the chemical stability of organic molecules within the host regolith based on the presence and chemical reactivity of surface and atmospheric oxidants. Urey has been selected for the Pasteur payload on the European Space Agency's (ESA's) upcoming 2013 ExoMars rover mission. The diverse and effective capabilities of Urey make it an integral part of the payload and will help to achieve a large portion of the mission's primary scientific objective: "to search for signs of past and present life on Mars." This instrument is named in honor of Harold Urey for his seminal contributions to the fields of cosmochemistry and the origin of life.

Aubrey, AD, Cleaves HJ, Bada JL.  2009.  The Role of Submarine Hydrothermal Systems in the Synthesis of Amino Acids. Origins of Life and Evolution of Biospheres. 39:91-108.   10.1007/s11084-008-9153-2   AbstractWebsite

There is little consensus regarding the plausibility of organic synthesis in submarine hydrothermal systems (SHSs) and its possible relevance to the origin of life. The primary reason for the persistence of this debate is that most experimental high temperature and high-pressure organic synthesis studies have neglected important geochemical constraints with respect to source material composition. We report here the results of experiments exploring the potential for amino acid synthesis at high temperature from synthetic seawater solutions of varying composition. The synthesis of amino acids was examined as a function of temperature, heating time, starting material composition and concentration. Using very favorable reactant conditions (high concentrations of reactive, reduced species), small amounts of a limited set of amino acids are generated at moderate temperature conditions (similar to 125-175A degrees C) over short heating times of a few days, but even these products are significantly decomposed after exposure times of approximately 1 week. The high concentration dependence observed for these synthetic reactions are demonstrated by the fact that a 10-fold drop in concentration results in orders of magnitude lower yields of amino acids. There may be other synthetic mechanisms not studied herein that merit investigation, but the results are likely to be similar. We conclude that although amino acids can be generated from simple likely environmentally available precursors under SHS conditions, the equilibrium at high temperatures characteristic of SHSs favors net amino acid degradation rather than synthesis, and that synthesis at lower temperatures may be more favorable.

B
Bada, JL, Peterson RO, Schimmelmann A, Hedges REM.  1990.  Moose Teeth as Monitors of Environmental Isotopic Parameters. Oecologia. 82:102-106.   10.1007/bf00318540   Website
Bada, J.  1983.  Amino Acid Racemization dating of fossil bones from Zhouk. China Excahnge News. 11:4-6.
Bada, JL, McDonald GD.  1996.  Detecting amino acids on Mars. Analytical Chemistry. 68:A668-A673.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
Bada, JL.  1985.  Amino-Acid Racemization Dating of Fossil Bones. Annual Review of Earth and Planetary Sciences. 13:241-268.   10.1146/annurev.earth.13.1.241   Website
Bada, JL, McDonald GD.  1995.  Amino-Acid Racemization on Mars - Implications for the Preservation of Biomolecules from an Extinct Martian Biota. Icarus. 114:139-143.   10.1006/icar.1995.1049   AbstractWebsite

Using kinetic data, we have estimated the racemization half-lives and times for total racemization of amino acids under conditions relevant to the surface of Mars. Amino acids from an extinct martian biota maintained in a dry, cold (<250 K) environment would not have racemized significantly over the lifetime of the planet. Racemization would have taken place in environments where liquid water was present even for time periods of only a few million years following biotic extinction. The best preservation of both amino acid homochirality and nucleic acid genetic information associated with extinct martian life would be in the polar regions. (C) 1995 Academic Press, Inc.

Bada, JL, Kvenvold.Ka, Peterson E.  1973.  Racemization of Amino-Acids in Bones. Nature. 245:308-310.   10.1038/245308a0   Website
Bada, J.  1984.  Application of Amino Acid Racemization Dating of Fossil Bones and Teeth in problems of paleoanthropology. McGraw-Hill yearbook of science and technology. :87-89.
Bada, JL, Miller SL.  1969.  Kinetics of Hydration of Fumaric Acid Between pH 0 and 6. Journal of the American Chemical Society. 91:3948-&.   10.1021/ja01042a048   Website
Bada, JL, Glavin DP, McDonald GD, Becker L.  1998.  A search for endogenous amino acids in martian meteorite ALH84001. Science. 279:362-365.   10.1126/science.279.5349.362   AbstractWebsite

Trace amounts of glycine, serine, and alanine were detected in the carbonate component of the martian meteorite ALH84001 by high-performance liquid chromatography. The detected amino acids were not uniformly distributed in the carbonate component and ranged in concentration from 0.1 to 7 parts per million. Although the detected alanine consists primarily of the L enantiomer, low concentrations (<0.1 parts per million) of endogenous D-alanine may be present in the ALH84001 carbonates. The amino acids present in this sample of ALH84001 appear to be terrestrial in origin and similar to those in Allan Hills ice, although the possibility cannot be ruled out that minute amounts of some amino acids such as D-alanine are preserved in the meteorite.

Bada, J.  2003.  Origins of life. Oceanography. 16:98-104.
Bada, JL, Hoopes E, Ho M.  1982.  Combined Amino-Acids in Pacific-Ocean Waters. Earth and Planetary Science Letters. 58:276-284.   10.1016/0012-821x(82)90200-x   Website
Bada, JL, Helfman PM.  1975.  Amino-Acid Racemization Dating of Fossil Bones. World Archaeology. 7:160-&. AbstractWebsite
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Bada, JL, Chalmers JH, Cleaves HJ.  2016.  Is formamide a geochemically plausible prebiotic solvent? Physical Chemistry Chemical Physics. 18:20085-20090.   10.1039/c6cp03290g   AbstractWebsite

From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely been rare on the early Earth. There may have been mixed formamide-water solutions, but even in the presence of catalyst, solutions with >= 20 weight% water in formamide would not have produced significant amounts of prebiotic compounds. It might be feasible to produce relatively pure formamide by a rare occurrence of freezing formamide/water mixtures at temperatures lower than formamide's freezing point (2.55 degrees C) but greater than the freezing point of water. Because of the high density of formamide ice it would have sunk and accumulated at the bottom of the solution. If the remaining water froze on the surface of this ice, and was then removed by a sublimation-ablation process, a small amount of pure formamide ice might have been produced. In addition a recent report suggested that similar to 85 weight% formamide could be prepared by a geochemical type of fractional distillation process, offering another possible route for prebiotic formamide production.

Bada, JL.  1972.  Dating of Fossil Bones Using Racemization of Isoleucine. Earth and Planetary Science Letters. 15:223-&.   10.1016/0012-821x(72)90167-7   Website