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Helfman, PM, Bada JL.  1975.  Aspartic-Acid Racemization in Tooth Enamel from Living Humans. Proceedings of the National Academy of Sciences of the United States of America. 72:2891-2894.   10.1073/pnas.72.8.2891   Website
Bada, JL, Mitchell E, Kemper B.  1983.  Aspartic-Acid Racemization in Narwhal Teeth. Nature. 303:418-420.   10.1038/303418a0   Website
Schroeder, RA, Bada JL.  1978.  Aspartic-Acid Racemization in Late Wisconsin Lake-Ontario Sediments. Quaternary Research. 9:193-204.   10.1016/0033-5894(78)90067-4   Website
Masters, PM, Bada JL, Zigler JS.  1977.  Aspartic-Acid Racemization in Human Lens During Aging and in Cataract Formation. Nature. 268:71-73.   10.1038/268071a0   Website
Masters, PM, Bada JL, Zigler JS.  1978.  Aspartic-Acid Racemization in Heavy Molecular-Weight Crystallins and Water-Insoluble Protein from Normal Human Lenses and Cataracts. Proceedings of the National Academy of Sciences of the United States of America. 75:1204-1208.   10.1073/pnas.75.3.1204   Website
Helfman, PM, Bada JL.  1976.  Aspartic-Acid Racemization in Dentin as a Measure of Aging. Nature. 262:279-281.   10.1038/262279b0   Website
Ike, D, Bada JL, Masters PM, Kennedy G, Vogel JC.  1979.  Aspartic-Acid Racemization and Radiocarbon Dating of an Early Milling Stone Horizon Burial in California. American Antiquity. 44:524-530.   10.2307/279550   Website
Brinton, KL, Bada JL.  1995.  Aspartic-Acid Racemization and Protein Diagenesis in Corals over the Last 350 Years - Comment. Geochimica Et Cosmochimica Acta. 59:415-416.Website
Bada, JL.  1985.  Aspartic-Acid Racemization Ages of California Paleoindian Skeletons. American Antiquity. 50:645-647.   10.2307/280327   Website
Skelley, AM, Cleaves HJ, Jayarajah CN, Bada JL, Mathies RA.  2006.  Application of the mars organic analyzer to nucleobase and amine biomarker detection. Astrobiology. 6:824-837.   10.1089/ast.2006.6.824   AbstractWebsite

The Mars Organic Analyzer (MOA), a portable microfabricated capillary electrophoresis instrument being developed for planetary exploration, is used to analyze a wide variety of fluorescamine-labeled amine-containing biomarker compounds, including amino acids, mono-and diaminoalkanes, amino sugars, nucleobases, and nucleobase degradation products. The nucleobases cytosine and adenine, which contain an exocyclic primary amine, were effectively labeled, separated, and detected at concentrations < 500 nM. To test the general applicability of the MOA for biomarker detection, amino acids and mono- and diamines were extracted from bacterial cells using both hydrolysis and sublimation followed by analysis. The extrapolated limit of detection provided by the valine biomarker was similar to 4 x 10(3) cells per sample. Products of an NH4CN polymerization that simulate a prebiotic synthesis were also successfully isolated via sublimation and analyzed. Adenine and alanine/serine were detected with no additional sample cleanup at 120 +/- 13 mu M and 4.1 +/- mu M, respectively, corresponding to a reaction yield of 0.04% and 0.0003%, respectively. This study demonstrates that the MOA provides sensitive detection and analysis of low levels of a wide variety of amine-containing organic compounds from both biological and abiotic sources.

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.
Masters, PM, Bada J.  1978.  Antiquity of human beings in America: Evidence derived from amino acid racemization of paleo Indian. Occasional papers in methods and tehories i n California Archeology. . 2:16-24.
Bada, JL, Miller SL.  1968.  Ammonium Ion Concentration in Primitive Ocean. Science. 159:423-&.   10.1126/science.159.3813.423   Website
Lee, C, Bada JL, Peterson E.  1976.  Amino-Acids in Modern and Fossil Woods. Nature. 259:183-186.   10.1038/259183a0   Website
Lee, C, Bada JL.  1975.  Amino-Acids in Equatorial Pacific Ocean Water. Earth and Planetary Science Letters. 26:61-68.   10.1016/0012-821x(75)90177-6   Website
Bada, JL, Schroeder RA.  1975.  Amino-Acid Racemization Reactions and Their Geochemical Implications. Naturwissenschaften. 62:71-79. AbstractWebsite
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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, Brown SE.  1980.  Amino-Acid Racemization in Living Mammals - Biochronological Applications. Trends in Biochemical Sciences. 5:R3-R5.   10.1016/s0968-0004(80)80800-0   AbstractWebsite
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Bada, JL, Wang XS, Poinar HN, Paabo S, Poinar GO.  1994.  Amino-Acid Racemization in Amber-Entombed Insects - Implications for DNA Preservation. Geochimica Et Cosmochimica Acta. 58:3131-3135.   10.1016/0016-7037(94)90185-6   AbstractWebsite

DNA depurination and amino acid racemization take place at similar rates in aqueous solution at neutral pH. This relationship suggests that amino acid racemization may be useful in accessing the extent of DNA chain breakage in ancient biological remains. To test this suggestion, we have investigated the amino acids in insects entombed in fossilized tree resins ranging in age from <100 years to 130 million years. The amino acids present in 40 to 130 million year old amber-entombed insects resemble those in a modern fly and are probably the most ancient, unaltered amino acids found so far on Earth. In comparison to other geochemical environments on the surface of the Earth, the amino acid racemization rate in amber insect inclusions is retarded by a factor of > 10(4). These results suggest that in amber insect inclusions DNA depurination rates would also likely be retarded in comparison to aqueous solution measurements, and thus DNA fragments containing many hundreds of base pairs should be preserved. This conclusion is consistent with the reported successful retrieval of DNA sequences from amber-entombed organisms.

Bada, JL, Hoopes E, Darling D, Dungworth G, Kessels HJ, Kvenvolden KA, Blunt DJ.  1979.  Amino-Acid Racemization Dating of Fossil Bones .1. Inter-Laboratory Comparison of Racemization Measurements. Earth and Planetary Science Letters. 43:265-268.   10.1016/0012-821x(79)90210-3   AbstractWebsite
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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, Helfman PM.  1975.  Amino-Acid Racemization Dating of Fossil Bones. World Archaeology. 7:160-&. AbstractWebsite
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