gc-based-detection-aldononitrile-acetate-derivatized-glucosamine

GC-based Detection of Aldononitrile Acetate Derivatized Glucosamine and Muramic Acid for Microbial Residue Determination in Soil

Quantitative approaches to characterizing microorganisms are crucial for a broader understanding of the microbial status and function within ecosystems. ...

University of Wisconsin, Madison

University of Florida 

The muramic acid (MurA) assay is a powerful tool for the detection and quantification of bacteria with no need to enrich samples by culturing. However, the analysis of MurA in mixed biological and environmental matrices is potentially more complex than analysis in isolated bacterial cells. In this study, we employed one commonly used procedure for extraction of MurA from environmental samples and found that the presence of streptomycin interfered with the determination of MurA by creating chemical species that coeluted with the aldononitrile derivative of MurA prepared in this method. On a molar basis, streptomycin yields a signal that is approximately 0.67 times that of MurA. Mass spectrometry analysis confirmed that the interference from hydrolyzed streptomycin is not actually by MurA, but rather is likely to be N-methyl glucosamine. Because streptomycin is widely applied for selective growth of eukaryotes both in situ and in vitro, our findings may have implications for the significance of results from MurA assays. We conclude that MurA remains an effectual bacterial biomarker due to its unique bacterial origin, but care must be applied in interpreting results from the assay when performed in the presence of streptomycin.

Reliability of muramic acid as a bacterial biomarker is influenced by methodological artifacts from streptomycin.

Leaf-cutter ants use fresh plant material to grow a mutualistic fungus that serves as the ants' primary food source. Within fungus gardens, various plant compounds are metabolized and transformed into nutrients suitable for ant consumption. This symbiotic association produces a large amount of refuse consisting primarily of partly degraded plant material. A leaf-cutter ant colony is thus divided into two spatially and chemically distinct environments that together represent a plant biomass degradation gradient. Little is known about the microbial community structure in gardens and dumps or variation between lab and field colonies.

Article	Year
Ecology\| PubMed ID: 16602287	2006
Ecology\| PubMed ID: 17601131	2007
Microbial ecology\| PubMed ID: 17912579	2008
Reliability of muramic acid as a bacterial biomarker is influenced by methodological artifacts from streptomycin. Microbial ecology\| PubMed ID: 18587610	2009
Journal of chromatography. A\| PubMed ID: 19497577	2009
Microbial community structure of leaf-cutter ant fungus gardens and refuse dumps. PloS one\| PubMed ID: 20360970	2010
Nature reviews. Microbiology\| PubMed ID: 21113179	2011
Journal of microbiological methods\| PubMed ID: 21621564	2011

Teri C. Balser

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