A Lipid Extraction and Analysis Method for Characterizing Soil Microbes in Experiments with Many Samples.

Microbial communities are important drivers and regulators of ecosystem processes. To understand how management of ecosystems may affect microbial communities, a relatively precise but effort-intensive technique to assay microbial community composition is phospholipid fatty acid (PLFA) analysis. PLFA was developed to analyze phospholipid biomarkers, which can be used as indicators of microbial biomass and the composition of broad functional groups of fungi and bacteria.

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. Current strategies for microbial analysis include both traditional laboratory culture-dependent techniques and those based on direct extraction and determination of certain biomarkers. Few among the diversity of microbial species inhabiting soil can be cultured, so culture-dependent methods introduce significant biases, a limitation absent in biomarker analysis.

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

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.

Comparisons of human-cell-based and submitochondrial particle bioassay responses to the MEIC compounds in reference to human toxicity data.

Toxicity results from submitochondrial particle (SMP) bioassays were compared to results from multiple human-cell-based assays to evaluate the SMP tests' ability to indicate cellular toxicity. Correlation analyses between cell-based and SMP responses were conducted on a series of diverse chemicals of human toxicologic interest chosen in the Multicentre Evaluation of In vitro Cytotoxicity (MEIC) study and suggest a high degree of ordering. The r(2) correlation coefficient obtained when comparing the log-transformed SMP results to the average cellular response for all compounds was 0.