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Bump, JK, Fox-Dobbs K, Bada JL, Koch PL, Peterson RO, Vucetich JA.  2007.  Stable isotopes, ecological integration and environmental change: wolves record atmospheric carbon isotope trend better than tree rings. Proceedings of the Royal Society B-Biological Sciences. 274:2471-2480.   10.1098/rspb.2007.0700   AbstractWebsite

Large-scale patterns of isotope ratios are detectable in the tissues of organisms, but the variability in these patterns often obscures detection of environmental trends. We show that plants and animals at lower trophic levels are relatively poor indicators of the temporal trend in atmospheric carbon isotope ratios (delta C-13) when compared with animals at higher trophic levels. First, we tested how differences in atmospheric delta C-13 values were transferred across three trophic levels. Second, we compared contemporary delta C-13 trends (1961 - 2004) in atmospheric CO2 to delta C-13 patterns in a tree species ( jack pine, Pinus banksiana), large herbivore (moose, Alces alces) and large carnivore (grey wolf, Canis lupus) from North America. Third, we compared palaeontological (approx. 30 000 to 12 000 14 C years before present) atmospheric CO2 trends to delta C-13 patterns in a tree species (Pinus flexilis, Juniperus sp.), a megaherbivore (bison, Bison antiquus) and a large carnivore (dire wolf, Canis dirus) from the La Brea tar pits ( southern California, USA) and Great Basin (western USA). Contrary to previous expectations, we found that the environmental isotope pattern is better represented with increasing trophic level. Our results indicate that museum specimens of large carnivores would best reflect large-scale spatial and temporal patterns of carbon isotopes in the palaeontological record because top predators can act as ecological integrators of environmental change.

Brinton, KLF, Engrand C, Glavin DP, Bada JL, Maurette M.  1998.  A search for extraterrestrial amino acids in carbonaceous Antarctic micrometeorites. Origins of Life and Evolution of Biospheres. 28:413-424.   10.1023/a:1006548905523   AbstractWebsite

Antarctic micrometeorites (AMMs) in the 100-400 mu m size range are the dominant mass fraction of extraterrestrial material accreted by the Earth today. A high performance Liquid chromatography (HPLC) based technique exploited at the limits of sensitivity has been used to search for the extraterrestrial amino acids alpha-aminoisobutyric acid (AIB) and isovaline in AMMs. Five samples, each containing about 30 to 35 grains, were analyzed. All the samples possess a terrestrial amino acid component, indicated by the excess of the L-enantiomers of common protein amino acids. In only one sample (A91) was AIB found to be present at a level significantly above the background blanks. The concentration of AIB (similar to 280 ppm), and the AIB/isovaline ratio (greater than or equal to 10), in this sample are both much higher than in CM chondrites. The apparently large variation in the AIB concentrations of the samples suggests that AIB may be concentrated in rare subset of micrometeorites. Because the AIB/isovaline ratio in sample A91 is much larger than in CM chondrites, the synthesis of amino acids in the micrometeorite parent bodies might have involved a different process requiring an HCN-rich environment, such as that found in comets. If the present day characteristics of the meteorite acid micrometeorite fluxes can be extrapolated back in time, then the flux of large carbonaceous micrometeorites could have contributed to the inventory of prebiotic molecules on the early Earth.

Brinton, KLF, Bada JL.  1996.  A reexamination of amino acids in lunar soils: Implications for the survival of exogenous organic material during impact delivery. Geochimica Et Cosmochimica Acta. 60:349-354.   10.1016/0016-7037(95)00404-1   AbstractWebsite

Using a sensitive high performance liquid chromatography technique, we have analyzed both the hot water extract and the acid hydrolyzed hot water extract of lunar soil collected during the Apollo 17 mission. Both free amino acids and those derived from acid labile precursors are present at a level of roughly 15 ppb. Based on the D/L amino acid ratios, the free alanine and aspartic acid observed in the hot water extract can be entirely attributed to terrestrial biogenic contamination. However, in the acid labile fraction, precursors which yield amino acids are apparently present in the lunar soil. The amino acid distribution suggests that the precursor is probably solar wind implanted HCN. We have evaluated our results with regard to the meteoritic input of intact organic compounds to the moon based on an upper limit of less than or equal to 0.3 ppb for alpha-aminoisobutyric acid, a non-protein amino acid which does not generally occur in terrestrial organisms and which is not a major amino acid produced from HCN, but which is a predominant amino acid in many carbonaceous chondrites. We find that the survival of exogenous organic compounds during lunar impact is less than or equal to 0.8%. This result represents an example of minimum organic impact survivability. This is an important first step toward a better understanding of similar processes on Earth and on Mars, and their possible contribution to the budget of prebiotic organic compounds on the primitive Earth.

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
Botta, O, Bada JL, Gomez-Elvira J, Javaux E, Selsis F, Summons R.  2008.  "Strategies of life detection": Summary and outlook. Space Science Reviews. 135:371-380.   10.1007/s11214-008-9357-9   Website
Botta, O, Bada JL.  2002.  Extraterrestrial organic compounds in meteorites. Surveys in Geophysics. 23:411-467.   10.1023/a:1020139302770   AbstractWebsite

Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

Botta, O, Martins Z, Emmenegger C, Dworkin JP, Glavin DP, Harvey RP, Zenobi R, Bada JL, Ehrenfreund P.  2008.  Polycyclic aromatic hydrocarbons and amino acids in meteorites and ice samples from LaPaz Icefield, Antarctica. Meteoritics & Planetary Science. 43:1465-1480. AbstractWebsite

We have analyzed ice samples and meteorites from the LaPaz region of Antarctica to investigate the composition of polycyclic aromatic hydrocarbons (PAHs) and amino acids with the goal to understand whether or not there is a compositional relationship between the two reservoirs. Four LL5 ordinary chondrites (OCs) and one CK carbonaceous chondrite were collected as part of the 2003/2004 ANSMET season. Ice samples collected from directly underneath the meteorites were extracted. In addition, exhaust particles from the snowmobiles used during the expedition were collected to investigate possible contributions from this source. The meteorite samples, the particulate matter and solid-state extracts of the ice samples and the exhaust filters were subjected to two-step laser mass spectrometry (L2MS) to investigate the PAH composition. For amino acids analysis, the meteorites were extracted with water and acid hydrolyzed, and the extracts were analyzed with offline OPA/NAC derivatization combined with liquid chromatography with UV fluorescence detection and time of flight mass spectrometry (LC-FC/ToF-MS). PAHs in the particulate matter of the ice were found to be qualitatively similar to the meteorite samples, indicating that micron-sized grains of the meteorite may be embedded in the ice samples. The concentration levels of dissolved PAHs in all the ice samples were found to be below the detection limit of the L2MS. The PAH composition of the snowmobile exhaust is significantly different to the one in particulate matter, making it an unlikely Source of contamination for Antarctic meteorites. The amino acids glycine, beta-alanine and gamma-amino-n-butyric acid that were detected at concentrations of 3 to 19 parts per billion (ppb) are probably indigenous to the Antarctic meteorites. Some of the LaPaz ice samples were also found to contain amino acids at concentration levels of 1 to 33 parts per trillion (ppt), in particular alpha-aminoisobutyric acid (AIB), an abundant non-protein amino acid of extraterrestrial Origin found in some carbonaceous chondrites. We hypothesize that this amino acid could have been extracted from Antarctic micrometeorites and the particulate matter of the meteorites during the concentration procedure of the ice samples.

Botta, O, Glavin DP, Kminek G, Bada JL.  2002.  Relative amino acid concentrations as a signature for parent body processes of carbonaceous chondrites. Origins of Life and Evolution of Biospheres. 32:143-163.   10.1023/a:1016019425995   AbstractWebsite

Most meteorites are thought to have originated from objects in the asteroid belt. Carbonaceous chondrites, which contain significant amounts of organic carbon including complex organic compounds, have also been suggested to be derived from comets. The current model for the synthesis of organic compounds found in carbonaceous chondrites includes the survival of interstellar organic compounds and the processing of some of these compounds on the meteoritic parent body. The amino acid composition of five CM carbonaceous chondrites, two CIs, one CR, and one CV3 have been measured using hot water extraction-vapor hydrolysis, OPA/NAC derivatization and high-performance liquid chromatography (HPLC). Total amino acid abundances in the bulk meteorites as well as the amino acid concentrations relative to glycine = 1.0 for beta-alanine, alpha-aminoisobutyric acid and D-alanine were determined. Additional data for three Antarctic CM meteorites were obtained from the literature. All CM meteorites analyzed in this study show a complex distribution of amino acids and a high variability in total concentration ranging from similar to15 300 to similar to5800 parts per billion (ppb), while the CIs show a total amino acid abundance of similar to4300 ppb. The relatively (compared to glycine) high AIB content found in all the CMs is a strong indicator that Strecker-cyanohydrin synthesis is the dominant pathway for the formation of amino acids found in these meteorites. The data from the Antarctic CM carbonaceous chondrites are inconsistent with the results from the other CMs, perhaps due to influences from the Antarctic ice that were effective during their residence time. In contrast to CMs, the data from the CI carbonaceous chondrites indicate that the Strecker synthesis was not active on their parent bodies.

Boehm, MF, Bada JL.  1984.  Racemization of Aspartic-Acid and Phenylalanine in the Sweetener Aspartame at 100-Degrees-C. Proceedings of the National Academy of Sciences of the United States of America-Physical Sciences. 81:5263-5266.   10.1073/pnas.81.16.5263   Website
Boehm, MF, Bada JL.  1984.  Investigations of Invivo Methionine Racemization in Mammalian-Tissues. Biochemistry International. 8:603-608.Website
Bennett, RV, Cleaves HJ, Davis JM, Sokolov DA, Orlando TM, Bada JL, Fernandez FM.  2013.  Desorption Electrospray Ionization Imaging Mass Spectrometry as a Tool for Investigating Model Prebiotic Reactions on Mineral Surfaces. Analytical Chemistry. 85:1276-1279.   10.1021/ac303202n   AbstractWebsite

Mineral-assisted thermal decomposition of formamide (HCONH2) is a heavily studied model prebiotic reaction that has offered valuable insights into the plausible pathways leading to the chemical building blocks of primordial informational polymers. To date, most efforts have focused on the analysis of formamide reaction products released in solution, although several studies have examined the role of mineral catalysts in promoting this chemistry. We show here that the direct investigation of reactive mineral surfaces by desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) gives a new perspective on the important role of the mineral surface in the formation of reaction products. As a proof-of-principle example, we show that DESI-MSI allows interrogation of the molecular products produced on heterogeneous granite samples with minimal sample preparation. Purine and pyrimidine nucleobases and their derivatives are successfully detected by DESI-MSI, with a strong correlation of the spatial product distribution with the mineral microenvironment. To our knowledge, this study is the first application of DESI-MSI to the study of complex and porous mineral surfaces and their roles in chemical evolution. This DESI-MSI approach is generally applicable to a wide range of reactions or other processes involving minerals.

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.

Becker, L, Bada JL, Kemper K, Suslick KS.  1992.  The Sonoluminescence Spectrum of Seawater. Marine Chemistry. 40:315-320.   10.1016/0304-4203(92)90029-a   AbstractWebsite

The sonoluminescence spectra of seawater and of a sodium chloride solution were determined by irradiation with ultrasound at 20 kHz. Ultrasound creates sonoluminescence through the process of acoustic cavitation: the formation, growth and implosive collapse of bubbles in a liquid. The sonoluminescence spectra of both seawater and NaCl in water are characterized by an emission line at 589 nm from excited-state sodium. Excited-state Na atoms are produced from the reaction of Na+ with high-energy hydroxyl radicals formed directly during the cavitation event. Emission at 589nm could be useful in determining whether sonochemical processes associated with cavitation occur in breaking waves or other turbulent flows.

Becker, L, Glavin DP, Bada JL.  1997.  Polycyclic aromatic hydrocarbons (PAHs) in Antarctic Martian meteorites, carbonaceous chondrites and polar ice. Abstracts of Papers of the American Chemical Society. 213:240-GEOC.Website
Becker, L, Bada JL, Winans RE, Bunch TE.  1994.  Fullerenes in Allende Meteorite. Nature. 372:507-507.   10.1038/372507a0   Website
Becker, L, Poreda RJ, Bada JL.  1996.  Extraterrestrial helium trapped in fullerenes in the sudbury impact structure. Science. 272:249-252.   10.1126/science.272.5259.249   AbstractWebsite

Fullerenes (C-60 and C-70) in the Sudbury impact structure contain trapped helium with a He-3/He-4 ratio of 5.5 x 10(-4) to 5.9 x 10(-4). The He-3/He-4 ratio exceeds the accepted solar wind value by 20 to 30 percent and is higher by an order of magnitude than the maximum reported mantle value, Terrestrial nuclear reactions or cosmic-ray bombardment are not sufficient to generate such a high ratio. The He-3/He-4 ratios in the Sudbury fullerenes are similar to those found in meteorites and in some interplanetary dust particles. The implication is that the helium within the C-60 molecules at Sudbury is of extraterrestrial origin.

Becker, L, Evans TP, Bada JL.  1993.  Synthesis of C60h2 by Rhodium-Catalyzed Hydrogenation of C-60. Journal of Organic Chemistry. 58:7630-7631.   10.1021/jo00079a002   AbstractWebsite

Reduction of C60 with rhodium(0) on alumina and hydrogen in deuterated benzene (C6D6) at ambient temperature and pressure yields a mixture of hydrogenated compounds; C60H2 has been characterized as the major product in 14% yield based on H-1 NMR.

Becker, L, Bada JL, Winans RE, Hunt JE, Bunch TE, French BM.  1994.  Fullerenes in the 1.85-Billion-Year-Old Sudbury Impact Structure. Science. 265:642-645.   10.1126/science.11536660   AbstractWebsite

Fullerenes (C-60 and C-70) have been identified by laser desorption, laser desorption postionization, and high-resolution electron-impact mass spectrometry in shock-produced breccias (Onaping Formation) of the Sudbury impact structure in Ontario, Canada, The C-60 isotope is present at a level of a few parts per million. The fullerenes were likely synthesized within the impact plume from the carbon contained in the bolide. The oxidation of the fullerenes during the 1.85 billion years of exposure was apparently prevented by the presence of sulfur in the form of sulfide-silicate complexes associated with the fullerenes.

Becker, L, McDonald GD, Bada JL.  1993.  Carbon Onions in Meteorites. Nature. 361:595-595.   10.1038/361595a0   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.

Beaty, DW, Miller S, Zimmerman W, Bada J, Conrad P, Dupuis E, Huntsberger T, Ivlev R, Kim SS, Lee BG, Lindstrom D, Lorenzoni L, Mahaffy P, McNamara K, Papanastassiou D, Patrick S, Peters S, Rohatgi N, Simmonds JJ, Spray J, Swindle TD, Tamppari L, Treiman A, Wolfenbarger JK, Zent A.  2004.  Planning for a Mars in situ sample preparation and distribution (SPAD) system. Planetary and Space Science. 52:55-66.   10.1016/j.pss.2003.08.016   AbstractWebsite

For Mars in situ landed missions, it has become increasingly apparent that significant value may be provided by a shared system that we call a Sample Preparation and Distribution (SPAD) System. A study was conducted to identify the issues and feasibility of such a system for these missions that would provide common functions for: receiving a variety of sample types from multiple sample acquisition systems; conducting preliminary characterization of these samples with non-destructive science instruments and making decisions about what should happen to the samples; performing a variety of sample preparation functions- and, finally, directing the prepared samples to additional science instruments for further analysis. Scientific constraints on the functionality of the system were identified, such as triage, contamination management, and various sample preparation steps, e.g., comminution, splitting, rock surfacing, and sieving. Some simplifying strategies were recommended and an overall science flow was developed. Engineering functional requirements were also investigated and example architectures developed. Preliminary conclusions are that shared SPAD facility systems could indeed add value to future Mars in situ landed missions if they are designed to respond to the particular requirements and constraints of those missions, that such a system appears feasible for consideration, and that certain standards should be developed for key SPAD interfaces. (C) 2003 Elsevier Ltd. All rights reserved.

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.