Stable Isotope Ratios as a Tool in Microbial Forensics—Part 3. Effect of Culturing on Agar-containing Growth Media

    Volume 50, Issue 6 (November 2005)

    ISSN: 0022-1198

    CODEN: JFSOAD

    Published Online: 14 September 2005

    Page Count: 8


    Kreuzer-Martin, HW
    Stable Isotope Ratio Facility for Environmental Research, Salt Lake City, UT

    Ehleringer, JR

    Chesson, LA
    Stable Isotope Ratio Facility for Environmental Research, Salt Lake City, UT

    Lott, MJ

    (Received 17 December 2004; accepted 23 June 2005)

    Abstract

    Stable isotope ratios of hydrogen and oxygen in microbes have been shown to be functions of the corresponding isotope ratios of the water with which the culture medium was prepared, and thus to contain a potential geographic signal. Water can evaporate from agar (solid) media during culturing, changing its isotope ratios. Here we describe the effect of drying on the isotope ratios of water extracted from agar media and the H and O stable isotope ratios ratios of Bacillus subtilis spores cultured on agar. The δ2H vs δ18O relationship of water in Petri dish agar was surprisingly constant during evaporation regardless of the ambient relative humidity, making it possible to calculate the approximate isotope ratios of the original water, even in significantly evaporated agar. The H stable isotope ratios of spores cultured on agar remained relatively unchanged as the agar dried, but the O ratio became significantly enriched.


    Paper ID: JFS2004513

    DOI: 10.1520/JFS2004513

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    Title Stable Isotope Ratios as a Tool in Microbial Forensics—Part 3. Effect of Culturing on Agar-containing Growth Media
    Symposium , 0000-00-00
    Committee E30