In JoVE (1)
Articles by Harry W. Read in JoVE
A Lipid Extraction and Analysis Method for Characterizing Soil Microbes in Experiments with Many Samples Lawrence G. Oates1, Harry W. Read2, Jessica L. M. Gutknecht3, David S. Duncan1, Teri B. Balser4, Randall D. Jackson1 1Department of Agronomy and Great Lakes Bioenergy Research Center, University of Wisconsin - Madison, 2Department of Soil Science, University of Wisconsin - Madison, 3Department of Soil, Water, and Climate, University of Minnesota, 4Faculty of Science and Engineering, Curtin University The article describes a method that increases throughput while balancing effort and accuracy for extraction of lipids from the cell membranes of microorganisms for use in characterizing both total lipids and the relative abundance of indicator lipids to determine soil microbial community structure in studies with many samples.
Other articles by Harry W. Read on PubMed
Comparisons of Human-cell-based and Submitochondrial Particle Bioassay Responses to the MEIC Compounds in Reference to Human Toxicity Data Toxicology. Aug, 2002 | Pubmed ID: 12135617 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 0.75 (n=42). When specific mitochondrial inhibitors (to which SMP arc extremely sensitive) and toxic metals (which SMP modeled poorly) were removed, the correlation improved to 0.91 (n=34). When the SMP assay of each individual cell-based assay was compared to the average toxic response of all the cell-based assays for these 34 compounds, the SMP r(2) was greater than the median r(2) of the cell-based assays, indicating its ability to predict cell-based toxic responses with a high degree of accuracy. Comparisons of the SMP data to the human toxicity data are similar to the cell line assays, where removal of the specific mitochondrial toxicants and metals greatly improves the relationship.
Reliability of Muramic Acid As a Bacterial Biomarker is Influenced by Methodological Artifacts from Streptomycin Microbial Ecology. Apr, 2009 | Pubmed ID: 18587610 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.