2001 Annual Science Report
NASA Johnson Space Center Reporting | JUL 2000 – JUN 2001
New Technique Development and Application
New Technique Development and Application (dm)
This project is important because it is pushing the state-of-the-art for analysis and detection of key organic compounds in terrestrial and astromaterials. The project consists several distinct parts. First is the development and construction of a new and improved double laser system based on the original Stanford design.We have produced a new design which will increase sensitivity and increase spatial resolution from 20-30 micrometer down to <5 micrometer and possibly to 1micrometer. We have already acquired appropriate lasers and have submitted a proposal to a NASA to acquire funds to build a new double laser probe.
While waiting for additional funding, we are reducing and publishing additional data on ALH84001 and Nakhla, two of the martian meteorites which have been found by other groups to contain indigenous martian organic compounds. Only by probe-based mapping (laser probe, ion probe, etc.) will it be possible to relate specific compounds to the phases which carry them. The double laser mass spectrometer sysem has the potential to detect organic compounds down in the attomole range. Although it was originally claimed that the PAHs in ALH84001 were Antarctic contamination, we have now demonstrated that ALH84001 contains PAHs in concentrations and locations consistent with indigenous martian organics.
The second part of this project is the application of time-of-flight-secondary ion mass spectrometers TOF-SIMS to the difficult task of detecting and quantifying very small amounts of organic compounds on the surface of rocks, minerals, and fossils. We are currently using an instrument at Montana State University in collaboration with Ricep Avec. The advantage of this technique is that it can have rather high spatial resolution, on the order of 1 micrometer or less. Analysis maps can be made which correlate exactly with SEM maps made in the same instrument so that the exact location of each organic specie can be mapped onto a morphologic or BSE image. Identified ompounds include alkenes, alkanes, aromatic and polycyclic aromatic hydrocarbons. Less certain identification includes alkyl pyrroles and pyridyl. In addition to detecting the compounds, we have begun to develop quantitative techniques based on standards. In addition, we have documented the location of organic compounds in the samples and shown their spatial distributions using SEM images as a mapping base. Detection of hopenoids, known to be a very stable family of organic biomarkers, has also been demonstrated by this technique using standards of various concentrations. New results from both of these techniques have been published by our group or are in press.
Another part of this project is the development and testing of new combinations of fluorescent probes as applied to live or nonfossilized cells and biofilms. When properly used in the appropriate combinations, such probes can provide the following information on single cells, cell colonies, and complex biofilms: (1) physiological status, (2) specific metabolic activities, (3) gene expression, and (4) total cell densities. We are setting up a new laboratory at JSC to pursue these techniques.
A new and very sensitive method to detect microbial traces uses Limulus Amebocyte Lysate and Prophenoloxidase to detect LPS, glucan, and peptidoglycan down to subpicogram levels. Current efforts involve staining the reacted sample with fixed LALF with an antibody which binds to the reacted LALF and a gold-labeled protein and then detecting the stained material with optical and electron microscopes.
Team members at Los Alamos are continuing to develop sensitive techniques for detecting microbe fossils. Current results show AFM images of fossils as well as XPS analysis of fossil surfaces.
PROJECT MEMBERS:Simon Clemett
RELATED OBJECTIVES:Objective 1.0
Determine whether the atmosphere of the early Earth, hydrothermal systems or exogenous matter were significant sources of organic matter.
Define how ecophysiological processes structure microbial communities, influence their adaptation and evolution, and affect their detection on other planets.
Search for evidence of ancient climates, extinct life and potential habitats for extant life on Mars.
Refine planetary protection guidelines and develop protection technology for human and robotic missions.