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Bada, JL.  2009.  Enantiomeric excesses in the Murchison meteorite and the origin of homochirality in terrestrial biology. Proceedings of the National Academy of Sciences of the United States of America. 106:E85-E85.   10.1073/pnas.0906490106   Website
Bada, J, Shou MY.  1980.  Kinetics and mechanics of amino acid racemization in aqueous solution and bones. Biogeochemistry of amino acids. Ed: Hare, P. E, Hoering, T. C, King, K.
Bada, JL.  1991.  Amino-Acid Cosmogeochemistry. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences. 333:349-358.   10.1098/rstb.1991.0084   AbstractWebsite

Amino acids are ubiquitous components of living organisms and as a result they are widely distributed on the surface of the Earth. Whereas only 20 amino acids are found in proteins, a much more diverse mixture of amino acids has been detected in carbonaceous meteorites. Amino acids in living organisms consist exclusively of the L-enantiomers, but in meteorites, amino acids with chiral carbons are present as racemic mixtures. Protein amino acids undergo a variety of diagenetic reactions that produce some other amino acids but not the unique amino acids present in meteorites. Nevertheless, trace quantities of meteoritic amino acids may occur on the Earth, either as a result of bolide impact or from the capture of cosmic dust particles. The ensemble of amino acids present on the early Earth before life existed was probably similar to those in prebiotic experiments and meteorites. This generates a question about why the L-amino acids on which life is based were selected.

Bada, J.  2003.  Origins of life. Oceanography. 16:98-104.
Bada, JL, Protsch R, Schroede.Ra.  1973.  Racemization Reaction of Isoleucine Used as a Paleotemperature Indicator. Nature. 241:394-395.   10.1038/241394a0   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, 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, Finkel R.  1983.  The upper pleistocene peopling of the New World: evidence derived from Radiocarbon, Amino acid racemization and Uranium serius dating. Quaternary coastline and marine archeology: towards the prehistory of land bridges and continental shelves. ( Masters PM, Flemming NC, Eds.).:463-479., London: Academic Press
Bada, JL.  1995.  Cold Start. Sciences-New York. 35:21-25.Website
Bada, JL, Ehrenfreund P, Grunthaner F, Blaney D, Coleman M, Farrington A, Yen A, Mathies R, Amudson R, Quinn R, Zent A, Ride S, Barron L, Botta O, Clark B, Glavin D, Hofmann B, Josset JL, Rettberg P, Robert F, Sephton M.  2008.  Urey: Mars Organic and Oxidant Detector. Space Science Reviews. 135:269-279.   10.1007/s11214-007-9213-3   AbstractWebsite

One of the fundamental challenges facing the scientific community as we enter this new century of Mars research is to understand, in a rigorous manner, the biotic potential both past and present of this outermost terrestrial-like planet in our solar system. Urey: Mars Organic and Oxidant Detector has been selected for the Pasteur payload of the European Space Agency's (ESA's) ExoMars rover mission and is considered a fundamental instrument to achieve the mission's scientific objectives. The instrument is named Urey in recognition of Harold Clayton Urey's seminal contributions to cosmochemistry, geochemistry, and the study of the origin of life. The overall goal of Urey is to search for organic compounds directly in the regolith of Mars and to assess their origin. Urey will perform a groundbreaking investigation of the Martian environment that will involve searching for organic compounds indicative of life and prebiotic chemistry at a sensitivity many orders of magnitude greater than Viking or other in situ organic detection systems. Urey will perform the first in situ search for key classes of organic molecules using state-of-the-art analytical methods that provide part-per-trillion sensitivity. It will ascertain whether any of these molecules are abiotic or biotic in origin and will evaluate the survival potential of organic compounds in the environment using state-of-the-art chemoresistor oxidant sensors.

Bada, JL, Schoeninger MJ, Schimmelmann A.  1989.  Isotopic Fractionation During Peptide-Bond Hydrolysis. Geochimica Et Cosmochimica Acta. 53:3337-3341.   10.1016/0016-7037(89)90114-2   Website
Bada, JL, Schroede.Ra.  1972.  Racemization of Isoleucine in Calcareous Marine Sediments - Kinetics and Mechanism. Earth and Planetary Science Letters. 15:1-&.   10.1016/0012-821x(72)90022-2   Website
Bada, JL, Miller SL.  1968.  Ammonium Ion Concentration in Primitive Ocean. Science. 159:423-&.   10.1126/science.159.3813.423   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, Bigham C, Miller SL.  1994.  Impact Melting of Frozen Oceans on the Early Earth - Implications for the Origin of Life. Proceedings of the National Academy of Sciences of the United States of America. 91:1248-1250.   10.1073/pnas.91.4.1248   AbstractWebsite

Without sufficient greenhouse gases in the atmosphere, the early Earth would have become a permanently frozen planet because the young Sun was less luminous than it is today. Several resolutions to this faint young Sun-frozen Earth paradox have been proposed, with an atmosphere rich in CO2 being the one generally favored. However, these models assume that there were no mechanisms for melting a once frozen ocean. Here we show that bolide impacts between about 3.6 and 4.0 billion years ago could have episodically melted an ice-covered early ocean. Thaw-freeze cycles associated with bolide impacts could have been important for the initiation of abiotic reactions that gave rise to the first living organisms.

Bada, JL, Sephton MA, Ehrenfreund P, Mathies RA, Skelley AM, Grunthaner FJ, Zent AP, Quinn RC, Josset JL, Robert F, Botta O, Glavin DP.  2005.  New strategies to detect life on Mars. Astronomy & Geophysics. 46:26-27. AbstractWebsite

The quest to determine whether life existed, or still exists, on Mars continues with several missions planned for the red planet by both the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) in the next few decades. One instrument designed for these missions is the Mars Organic Detector (MOD), which uses a new approach to achieve exceptionally high detection sensitivities and analysis capabilities for key bio-organic compounds. MOD is scheduled to fly in the ESA ExoMars mission early next decade and will attempt to answer the question of whether we are alone in the solar system. Here the MOD team explains why we have reason to be optimistic about uncovering the organic secrets of Mars.

Bada, JL, Schroede.Ra, Protsch R, Berger R.  1974.  Concordance of Collagen-Based Radiocarbon and Aspartic-Acid Racemization Ages. Proceedings of the National Academy of Sciences of the United States of America. 71:914-917.   10.1073/pnas.71.3.914   Website
Bada, JL, Luyendyk BP.  1971.  Route to Late Cenozoic Temperature History. Science. 172:503-&.Website