Engineering topics

Griffin, C.

Publications and source records attributed to Griffin, C..

5 records

NASA NTRS2001

Microbial Contamination of Allende and Murchison Carbonaceous Chondrites; Developing a Protocol for Life Detection in Extraterrestrial Materials Using Biotechnology

The arguments used to refute the McKay et al., (1996) hypothesis of possible Martian life in ALH84001 failed to use contamination of the meteorite as a source. This has worrying implications for our ability to detect terrestrial microbiota in meteorites and therefore any potential extraterrestrial biosignatures in both meteorites and possible returned samples. We report on imaging and microbial culturing of both Allende and Murchison carbonaceous chondrites and on the use of molecular biology techniques on a sample of Allende. Contaminating fungi and bacteria were observed (in the case of Murchison) and cultured from both meteorites. DNA was successfully extracted and subsequent PCR showed the presence of both bacterial and fungal DNA although no Archaea were detected. These results show that it is possible to use molecular biological techniques on very small quantities (300 mg) of extraterrestrial material.

Steele, A.↗

NASA NTRS2000

The Microbiological Contamination of Meteorites: A Null Hypothesis

Using 4 different techniques we have studied 9 meteorites including the Martian meteorites ALH84001 and Nakhla for terrestrial contamination in all 9 we have found evidence of terrestrial microorganisms.

Steele, A.↗

NASA NTRS2000

Electron Microscopy Studies, Surface Analysis and Microbial Culturing Experiments on a Depth Profile Through Martian Meteorite Nakhla

Combined electron microscopy studies and culturing experiments have shown that Nakhla became contaminated with recent terrestrial microorganisms. Additional surface analysis detected an as yet unknown organic species which may represent a biomarker.

Toporski, J. K. W.↗

NASA NTRS2000

The Direct Extraction of DNA from Allende

We have devised a protocol for the direct extraction of DNA from extraterrestrial materials and have successfully applied it to the Allende meteorite.

Whitby, C.↗

NASA NTRS1994

The Spectrum of Titan near 3.4 Micron: Comparison of Spectral Features to Organic Molecules

In August 1993 we observed the spectrum of Titan from 2.9 to 4.1 micrometers at a resolving power of R=500-1000 (dw approx. 2-4 per cm). The spectrum shows, as expected, a strong absorption throughout this region from three strong bands Of CH4. However, comparison of the spectrum to simple radiative transfer models and to the spectrum of Jupiter reveal some interesting differences. A broad emission feature that we attribute to CH4 is centered at 3.3 micrometers. At 3.45 micrometers we see a distinct narrow absorption feature that is present in both the Jupiter and laboratory spectrum, but only when other features, absent in the Titan spectrum, are also present. In our attempt to understand the origin of this spectral feature we have compared the spectrum to CH4 and other organic molecules. Interesting similarities appear between the aliphatic hydrocarbons (CH2 and CH3 groups) seen in laboratory organics and the Titan spectrum, but only if we assume that the shorter wavelength feature (CH3) is masked by the broad CH4 emission. A second problem with the explanation is that like column abundance of organic haze (Toon et al. 1991) is insufficient to provide the required number of molecules to create a spectral feature with tau approx. 1. Laboratory organics produced through a variety of processes have been compared to the Titan spectrum and the results arc presented.

Pendleton, Yvonne↗