Journal Published Online: 14 September 2005
Volume 50, Issue 6

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

CODEN: JFSCAS

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.

Author Information

Kreuzer-Martin, HW
University of Utah, Salt Lake City, UT
Chesson, LA
University of Utah, Salt Lake City, UT
Lott, MJ
University of Utah, Salt Lake City, UT Iso Forensics, Inc., Salt Lake City, UT
Ehleringer, JR
University of Utah, Salt Lake City, UT Iso Forensics, Inc., Salt Lake City, UT
Pages: 8
Price: $25.00
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Stock #: JFS2004513
ISSN: 0022-1198
DOI: 10.1520/JFS2004513