The isotopic distribution of the atoms composing the molecules of microorganisms is a function of the substrates used by the organisms. The stable isotope content of an organism is fixed so long as no further substrate consumption and biosynthesis occurs, while the radioactive isotopic content decays over time. The distribution of stable isotopes of C, N, O and H in heterotrophic microorganisms is a direct function of the culture medium, and therefore the stable isotope composition can be used to associate samples with potential culture media and also with one another. The 14C content depends upon the 14C content, and therefore the age, of the organic components of the culture medium, as well as on the age of the culture itself. Stable isotope signatures can thus be used for sample matching, to associate cultures with specific growth media, and to predict characteristics of growth media.
Revised: January 10, 2012 |
Published: January 3, 2012
Citation
Kreuzer H.W. 2012.Stable Isotope Signatures for Microbial Forensics. In Chemical and Physical Signatures for Microbial Forensics, edited by JB Cliff, HW Kreuzer, CJ Ehrhardt and DS Wunschel. 89-108. New York, New York:Humana Press.PNNL-SA-62126.