Open AccessChemical markers for bacteria in extraterrestrial samples
Author(s) -
Fox Alvin
Publication year - 2002
Publication title -
the anatomical record
Language(s) - English
Resource type - Journals
eISSN - 1097-0185
pISSN - 0003-276X
DOI - 10.1002/ar.10152
Subject(s) - astrobiology , extraterrestrial life , meteorite , mars exploration program , earth (classical element) , lunar soil , martian , environmental science , regolith , contamination , environmental chemistry , interplanetary dust cloud , exploration of mars , chemistry , solar system , physics , astronomy , biology , ecology
Interplanetary missions to collect pristine Martian surface samples for analysis of organic molecules, and to search for evidence of life, are in the planning phases. The only extraterrestrial samples currently on Earth are lunar dust and rocks, brought back by the Apollo (U.S.) and Luna (Soviet Union) missions to the moon, and meteorites. Meteorites are contaminated when they pass through the Earth's atmosphere, and during environmental exposure on Earth. Lunar fines have been stored on Earth for over 30 years under conditions designed to avoid chemical but not microbiological contamination. It has been extremely difficult to draw firm conclusions about the origin of chemicals (including amino acids) in extraterrestrial samples. Of particular concern has been the possibility of bacterial contamination. Recent work using state‐of‐the‐art gas chromatography tandem mass spectrometry (GC‐MS/MS) has dramatically lowered the chemical background, allowing a clear demonstration that lunar fines are remarkably different from terrestrial dust in that they generally lack certain chemical markers (muramic acid and 3‐hydroxy fatty acids) characteristic of Earth's bacteria. Thus, lunar dust might be used as a negative control, in conjunction with GC‐MS/MS analyses, in future analytical studies of lunar dust and meteorites. Such analyses may also be important in studies designed to search for the presence of life on Mars. Anat Rec 268:180–185, 2002. © 2002 Wiley‐Liss, Inc.