Environmental Molecular Sciences Laboratory

About: Environmental Molecular Sciences Laboratory is a facility organization based out in Richland, Washington, United States. It is known for research contribution in the topics: Mass spectrometry & Ion. The organization has 1471 authors who have published 3010 publications receiving 169961 citations.

Proteome Analysis of Liver Cells Expressing a Full-Length Hepatitis C Virus (HCV) Replicon and Biopsy Specimens of Posttransplantation Liver from HCV-Infected Patients

Abstract: The development of a reproducible model system for the study of hepatitis C virus (HCV) infection has the potential to significantly enhance the study of virus-host interactions and provide future direction for modeling the pathogenesis of HCV. While there are studies describing global gene expression changes associated with HCV infection, changes in the proteome have not been characterized. We report the first large-scale proteome analysis of the highly permissive Huh-7.5 cell line containing a full-length HCV replicon. We detected >4,200 proteins in this cell line, including HCV replicon proteins, using multidimensional liquid chromatographic (LC) separations coupled to mass spectrometry. Consistent with the literature, a comparison of HCV replicon-positive and -negative Huh-7.5 cells identified expression changes of proteins involved in lipid metabolism. We extended these analyses to liver biopsy material from HCV-infected patients where a total of >1,500 proteins were detected from only 2 mug of liver biopsy protein digest using the Huh-7.5 protein database and the accurate mass and time tag strategy. These findings demonstrate the utility of multidimensional proteome analysis of the HCV replicon model system for assisting in the determination of proteins/pathways affected by HCV infection. Our ability to extend these analyses to the highly complex proteome of small liver biopsies with limiting protein yields offers the unique opportunity to begin evaluating the clinical significance of protein expression changes associated with HCV infection.

High-efficiency capillary isoelectric focusing of peptides.

Abstract: Several approaches are presently being developed for global proteome characterization that are based upon the analysis of polypeptide mixtures resulting from digestion of (often complex) mixtures of proteins. Improved methods for peptide analysis are needed that provide for sample concentration, higher resolution separations, and direct compatibility with mass spectrometry. In this work, methods for the high-efficiency capillary isoelectric focusing (CIEF) separation of peptides have been developed that provide for simultaneous sample concentration and separation according to peptide isoelectric point. Under typical nondenaturing CIEF conditions, peptides are concentrated approximately 500-fold, and peptides present at < 1 ng/ microL were detectable using conventional UV detection. CIEF separations of peptides provided much faster measurements of isoelectric points compared with conventional isoelectric focusing in gels. Very small differences in peptide isoelectric points (deltapI approximately 0.01) could be resolved, High-efficiency CIEF separations for complex peptide mixtures from tryptic digestion of yeast cytosol fractions were obtained and showed significant improvement over those obtained using capillary zone electrophoresis and packed capillary reversed-phase liquid chromatography.

Coupled Kinetics of Ferrihydrite Transformation and As(V) Sequestration under the Effect of Humic Acids: A Mechanistic and Quantitative Study.

Abstract: In natural environments, kinetics of As(V) sequestration/release is usually coupled with dynamic Fe mineral transformation, which is further influenced by the presence of natural organic matter (NOM). Previous work mainly focused on the interactions between As(V) and Fe minerals. However, there is a lack of both mechanistic and quantitative understanding on the coupled kinetic processes in the As(V)–Fe mineral–NOM system. In this study, we investigated the effect of humic acids (HA) on the coupled kinetics of ferrihydrite transformation into hematite/goethite and sequestration of As(V) on Fe minerals. Time-resolved As(V) and HA interactions with Fe minerals during the kinetic processes were studied using aberration-corrected scanning transmission electron microscopy, chemical extractions, stirred-flow kinetic experiments, and X-ray absorption spectroscopy. Based on the experimental results, we developed a mechanistic kinetics model for As(V) fate during Fe mineral transformation. Our results demonstrated ...

Thermal stability of MnBi magnetic materials

Abstract: MnBi has attracted much attention in recent years due to its potential as a rare-earth-free permanent magnet material. It is unique because its coercivity increases with increasing temperature, which makes it a good hard phase material for exchange coupling nanocomposite magnets. MnBi phase is difficult to obtain, partly because the reaction between Mn and Bi is peritectic, and partly because Mn reacts readily with oxygen. MnO formation is irreversible and harmful to magnet performance. In this paper, we report our efforts toward developing MnBi permanent magnets. To date, high purity MnBi (>90%) can be routinely produced in large quantities. The produced powder exhibits 74.6 emu g(-1) saturation magnetization at room temperature with 9 T applied field. After proper alignment, the maximum energy product (BH)max of the powder reached 11.9 MGOe, and that of the sintered bulk magnet reached 7.8 MGOe at room temperature. A comprehensive study of thermal stability shows that MnBi powder is stable up to 473 K in air.