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Principal Investigators Prof. Ron Crawford, Team Leader (microbiology)

Describing and Measuring Chemical Signatures of Life. Research Team. Principal Investigators Prof. Ron Crawford, Team Leader (microbiology) Dr. Mohammed M. Mojarradi, Team Leader (Jet Propulsion Laboratory) Prof. Rick Wells (microelectronics) Prof. Frank Cheng (chemistry)

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Principal Investigators Prof. Ron Crawford, Team Leader (microbiology)

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  1. Describing and Measuring Chemical Signatures of Life Research Team • Principal Investigators • Prof. Ron Crawford, Team Leader (microbiology) • Dr. Mohammed M. Mojarradi, Team Leader (Jet Propulsion Laboratory) • Prof. Rick Wells (microelectronics) • Prof. Frank Cheng (chemistry) • Prof. Chien Wai (chemistry) • Prof. Tony Anderson (mechanical engineering) • Senior Scientists • Dr. Andrzej Paszczynski (staff biochemist) • Dr. Qingyong Lang (postdoctoral chemist) • Students and Staff • Mr. Bruce Barnes (microelectronics Ph.D. candidate) • Ms. Lisa Allenbach (technical assistant) • Mr. Dan Erwin (undergraduate researcher) • Funding received from NASA/JPL on 11/30/99

  2. The Goal: To develop a suite of prototype devices that together will indicate the presence or absence of life beyond Earth. Assumptions: Life requires continual energy input, tapped in a controlled manner. - Metabolism Form of energy: Chemical energy The life forms we are seeking are living entities, not fossils. El

  3. H2, NH3/NH4+, CH4, H2S • Metal ions (Fe2+), Metals • Hydrocarbons Electron Donors - Reducing Agents e- Energy • O2, NO3-, SO2/SO3 • Metal Ions (Fe3+ and higher) Electron Acceptors - Oxidizing Agents

  4. e- e- e- e- e- e- e- e- e- e- Respiratory Chain (CH2O)n  - 0.70 volts NAD+ + H+ + 2e- NADH -0.32 volts FMN + 2H+ + 2e- FMNH2 -0.30 V FAD + 2H+ + 2e- FADH2 -0.22 V CoQ + 2H+ + 2e- CoQH2 0.04 V Cytochrome b (3+) e- Cytochrome b (2+) 0.07 V Cytochrome c1 (3+) e- Cytochrome c1 (2+) 0.023 V Cytochrome c (3+) e- Cytochrome c (2+) 0.025 V Cytochrome a (3+) e- Cytochrome a (2+) 0.029 V Cytochrome a3 (3+) e- Cytochrome a3 (2+) 0.055 V O2 + 4H+ + 4e- 2H2O +0.77 volts

  5. Water flow waterfall Vs. series of dams

  6. Waterfall vs. Dams • Regulation of water flow  metabolism • Control of energy utilization • More efficient utilization of energy • Storage of energy

  7. Electron transport agents range from –1.0 to +1.0 volt • In order to transport electrical current, agents must be able to undergo several reduction-oxidation (redox) cycles. Ox + ne- Red • Electrochemical properties - reversible, quasi-reversible • Detectable by voltammetric methods

  8. Sample Extraction Module • Sample will be obtained and life signature compounds (redox agents) extracted by either a chemical solvent or supercritical CO2 • Extracted compounds will be separated, probably by capillary electrophoresis (CE). • Components separated in the previous module will be detected here using voltammetric, spectral absorbance detectors, and MS/MS. • Data will be transmitted to Earth for processing. Compound Separation Module Detection Module Data Processing Module

  9. Methodology • Biological samples for validating methods • Pure cultures of representative soil bacteria • Pseudomonas stutzeri (gram negative, facultative) • Arthrobacter (gram positive, aerobic) • Bacillus (gram positive, facultative, endospores) • Sand containing various numbers of these bacteria • Real soils known to contain few active bacteria; e.g., hot or cold desert soils

  10. Structures of Model Compounds A Flavin: Riboflavin Protoporphyrin IX of Heme A Diphosphopyridine Nucleotide: NAD

  11. CE-ECD analysis of bacterial redox components Control Pseudomonas putida Arthrobactor 10 10 M standards 10 10 10

  12. Future Directions • Square-wave or Cyclic voltammetric CE detection: • Redox potential & concentration information. current potential Energy • Series of reversible redox agents over the range of -1 to +1 volts may indicate life retention time

  13. Possible Lab on a Chip Design The extraction module can be designed to handle either traditional solvents (e.g., DMF/ Borate / SDS or 1.0 M formic acid) or pressurized supercritical carbon dioxide.

  14. Prototype CE-Square Wave Voltammetry System Acknowledgement: AgilentTechnologies

  15. Continuing Work • Extraction / Analysis Methods: Additional Redox Molecules • Rigorously Test Miniaturized CE /SW-Voltammetry System with Standards and Soil Extracts • Additional Testing with Earth-based Soils (Craters of the Moon and others) • Develop Collaborations: Miniaturized ES-MS/MS • Completion of Primary Objective (4-6 Months: Finalize Conceptual Design of Life Detection System)

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